diff --git a/.Rbuildignore b/.Rbuildignore
index fd42ca0..9b757e4 100644
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -8,3 +8,4 @@
 ^CRAN-RELEASE$
 ^dev_notes$
 ^\.github$
+^data-raw$
diff --git a/DESCRIPTION b/DESCRIPTION
index a87431e..e9c5446 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -19,6 +19,8 @@ Imports:
         tools,
         utils
 Suggests:
+    countrycode,
+    cshapes,
     DBI,
     RSQLite,
     sf,
diff --git a/R/GNRS_local.R b/R/GNRS_local.R
index cfcc0a6..1d988ac 100644
--- a/R/GNRS_local.R
+++ b/R/GNRS_local.R
@@ -25,10 +25,44 @@
 #'   downloaded silently: the function reports what is missing and the call that
 #'   would fix it.  Set it to TRUE to allow an unattended build.
 #' @param quiet Suppress progress messages?
+#' @param history Historical political divisions: \code{"all"} (the default;
+#'   also matches former countries such as the USSR, Yugoslavia or
+#'   Czechoslovakia, flagging such matches, so a record named with a political
+#'   division that was ever accurate resolves), \code{"current"} (today's
+#'   divisions only, as the web service does), or \code{"at_date"} (as "all",
+#'   but a former country is accepted only if it existed at the record's date,
+#'   taken from an optional \code{date} column of years or ISO dates; a name
+#'   marked as former, such as "Former USSR", is accepted for any later date,
+#'   and a state or county that resolves within a successor is kept and flagged
+#'   whatever the date).  Needs the \code{"history"} component, built from
+#'   tables shipped with the package plus the CShapes historical boundaries,
+#'   which are read from the \code{cshapes} package when it is installed and
+#'   otherwise downloaded from the publisher (about 60 MB) when
+#'   \code{build_missing} allows building; with \code{history = "current"}
+#'   nothing beyond the ordinary components is needed.  When the component
+#'   cannot be prepared (a package not installed, a download declined), the
+#'   call says so and resolves current divisions only.
+#' @param tolerance_years With \code{history = "at_date"}, how many years
+#'   either side of a former country's existence a record date may fall.  A
+#'   single non-negative number.
 #' @return A data.frame with the same columns as \code{GNRS()}, one row per
-#'   input row in input order.  Scores are numeric rather than the character
-#'   strings the web service returns; identifiers are character, as the web
-#'   service returns them; empty values are "".
+#'   input row in input order.  With \code{history} other than "current",
+#'   further columns: \code{entity_key}, \code{is_historical},
+#'   \code{entity_valid_from}, \code{entity_valid_to}, \code{successors} (the
+#'   current countries descending from a matched former country),
+#'   \code{subnational_resolved_in} and \code{subnational_status} (a state or
+#'   county given under a former country is looked up within its successors;
+#'   "unverifiable" if none contains it), and \code{date_check}.  Whatever
+#'   \code{history} is, four further columns report a state or county that is
+#'   an alternative or superseded division rather than one the service knows
+#'   (a Swedish landskap, a Watsonian vice-county, a Norwegian county from
+#'   before the 2020 reform): \code{alt_division} (its name),
+#'   \code{alt_division_system}, \code{alt_division_level} and
+#'   \code{alt_division_extent_known} (whether the GADM units it covers are
+#'   recorded, so that a coordinate could be checked against it); "" or NA
+#'   for a row that resolved ordinarily.  Scores are numeric rather than the
+#'   character strings the web service returns; identifiers are character, as
+#'   the web service returns them; empty values are "".
 #' @note \strong{This is a new implementation and should be treated as beta.}
 #'   It is a port of the SQL the web service runs, resolving against the
 #'   service's own reference tables, so identifiers, standard names and codes
@@ -67,7 +101,10 @@ GNRS_local <- function(political_division_dataframe,
                        alternate_names = TRUE,
                        dir = gnrs_cache_dir(),
                        build_missing = interactive(),
-                       quiet = FALSE) {
+                       quiet = FALSE,
+                       history = c("all", "current", "at_date"),
+                       tolerance_years = 1) {
+  history <- match.arg(history)
   if (!inherits(political_division_dataframe, "data.frame")) {
     stop("political_division_dataframe should be a data.frame", call. = FALSE)
   }
@@ -78,13 +115,68 @@ GNRS_local <- function(political_division_dataframe,
   if (!is.logical(alternate_names) || length(alternate_names) != 1L || is.na(alternate_names)) {
     stop("alternate_names should be TRUE or FALSE", call. = FALSE)
   }
+  if (!is.numeric(tolerance_years) || length(tolerance_years) != 1L ||
+    !is.finite(tolerance_years) || tolerance_years < 0) {
+    stop("tolerance_years should be a single non-negative number", call. = FALSE)
+  }
 
   input <- gnrs_check_input(political_division_dataframe)
 
+  dates <- if (history == "at_date") {
+    if (!"date" %in% names(political_division_dataframe)) {
+      message("history = \"at_date\" but no date column: former countries are matched without a date check.")
+      NULL
+    } else {
+      gnrs_parse_record_date(political_division_dataframe$date)
+    }
+  } else {
+    NULL
+  }
+
+  # Alternative and superseded sub-national divisions (Swedish landskap, Watsonian
+  # vice-counties, Norwegian counties after the 2018 and 2020 reforms): shipped
+  # curation, nothing downloaded, so it is built on first use.
+  if (!gnrs_is_built("altdiv", dir)) {
+    if (!quiet) message("Building the alternative-division component (no download) ...")
+    gnrs_build_altdiv(dir = dir, quiet = TRUE)
+  }
+
   sources <- if (alternate_names) c("gnrs", "geonames") else "gnrs"
   if (!gnrs_require_sources(sources, dir = dir, build_missing = build_missing, quiet = quiet)) {
     return(invisible(NULL))
   }
+  # The history component is assembled from the curation shipped with the package and
+  # the user's own copy of CShapes (nothing derived from CShapes ships: it is CC BY-NC-SA
+  # 4.0 and the package is MIT). With the cshapes package installed that downloads
+  # nothing, so it happens on first use as it always did; without it CShapes has to be
+  # downloaded, which follows build_missing like every other download.
+  # When it cannot be prepared (a package missing, or a download declined), the
+  # call goes on with current divisions only, and says so, rather than returning
+  # nothing: the default build prepares the ordinary components only.
+  if (history != "current" && !gnrs_is_built("history", dir)) {
+    ready <- FALSE
+    need <- c("sf", "countrycode")[!vapply(c("sf", "countrycode"), requireNamespace, logical(1), quietly = TRUE)]
+    if (length(need)) {
+      message("history = \"", history, "\" needs the ", paste(need, collapse = " and "),
+              " package", if (length(need) > 1) "s" else "", ", which ",
+              if (length(need) > 1) "are" else "is", " not installed.")
+    } else if (!gnrs_is_built("cshapes", dir) && !requireNamespace("cshapes", quietly = TRUE) &&
+               !gnrs_require_sources("cshapes", dir = dir, build_missing = build_missing, quiet = quiet)) {
+      message("The CShapes data that history = \"", history, "\" needs was not built.")
+    } else {
+      if (!gnrs_is_built("cshapes", dir)) {
+        if (!quiet) message("Building the CShapes component from the cshapes package (no download) ...")
+        gnrs_build_cshapes(dir = dir, quiet = TRUE)
+      }
+      if (!quiet) message("Building the history component (no download) ...")
+      gnrs_build_history(dir = dir, quiet = TRUE)
+      ready <- TRUE
+    }
+    if (!ready) {
+      message("Resolving against current political divisions only (history = \"current\").")
+      history <- "current"
+    }
+  }
   if (!alternate_names && gnrs_is_built("geonames", dir)) {
     # Built but not wanted: the name table on disk includes the GeoNames
     # names, so they are set aside when loading
@@ -113,10 +205,26 @@ GNRS_local <- function(political_division_dataframe,
   if (!quiet && nrow(u) > 0) {
     message("Resolving ", nrow(u), " distinct political division", if (nrow(u) == 1) "" else "s", " ...")
   }
-  resolved <- gnrs_resolve(u, bb, threshold = threshold)
-
   m <- match(key, key[distinct])
-  gnrs_build_output(resolved[m, , drop = FALSE], input, threshold)
+  if (history == "current") {
+    resolved <- gnrs_resolve(u, bb, threshold = threshold)
+    return(gnrs_build_output(resolved[m, , drop = FALSE], input, threshold))
+  }
+
+  r <- gnrs_resolve_history(u, m, dates, bb, dir = dir, threshold = threshold,
+                            history = history, tolerance_years = tolerance_years,
+                            alternate_names = alternate_names)
+  out <- gnrs_build_output(r, input, threshold)
+  chr <- function(x) { x <- as.character(x); x[is.na(x)] <- ""; x }
+  out$entity_key <- chr(r$entity_key)
+  out$is_historical <- r$is_historical
+  out$entity_valid_from <- chr(r$entity_valid_from)
+  out$entity_valid_to <- chr(r$entity_valid_to)
+  out$successors <- chr(r$successors)
+  out$subnational_resolved_in <- chr(r$subnational_resolved_in)
+  out$subnational_status <- chr(r$subnational_status)
+  out$date_check <- chr(r$date_check)
+  out
 }
 
 #' Check the submitted data.frame and put it in a standard form
@@ -250,6 +358,14 @@ gnrs_build_output <- function(r, input, threshold) {
     user_id = input$user_id,
     stringsAsFactors = FALSE
   )
+  # A declared division belonging to another division system, recognised as itself
+  # rather than forced onto the nearest GADM unit. Appended after the service's own
+  # columns, as the history component's are: extent_known says whether the GADM units
+  # it covers are known, and so whether a coordinate can be checked against it.
+  out$alt_division <- chr(r$alt_division)
+  out$alt_division_system <- chr(r$alt_division_system)
+  out$alt_division_level <- chr(r$alt_division_level)
+  out$alt_division_extent_known <- r$alt_division_extent_known
   rownames(out) <- NULL
   out
 }
diff --git a/R/GNRS_local_citations.R b/R/GNRS_local_citations.R
index 93e83ab..1a0a053 100644
--- a/R/GNRS_local_citations.R
+++ b/R/GNRS_local_citations.R
@@ -108,11 +108,16 @@ GNRS_local_citations <- function(dir = gnrs_cache_dir(), bibtex_file = NULL, qui
         "GeoNames. Gazetteer (allCountries), file dated ", version,
         ". https://www.geonames.org/ (CC BY 4.0). Accessed ", accessed, "."
       )
-    } else {
+    } else if (source %in% c("history", "cshapes")) {
+      # the registry carries the full citation for these components
+      paste0(spec$citation, if (!is.na(accessed)) paste0(" Built ", accessed, ".") else "")
+    } else if (source == "geonames") {
       paste0(
         "GeoNames. Alternate names (alternateNamesV2), file dated ", version,
         ". https://www.geonames.org/ (CC BY 4.0). Accessed ", accessed, "."
       )
+    } else {
+      paste0(spec$full_name, ". ", spec$citation %||% spec$url)
     }
     rows[[length(rows) + 1]] <- data.frame(
       what = "source", name = spec$full_name, version = version,
diff --git a/R/local_altdiv.R b/R/local_altdiv.R
new file mode 100644
index 0000000..1ff4fb0
--- /dev/null
+++ b/R/local_altdiv.R
@@ -0,0 +1,178 @@
+# ===========================================================================
+# Alternative and superseded sub-national divisions
+#
+# A large part of the record stream declares a state or county that is not a GADM
+# division: Swedish landskap and lappmarker, British Watsonian vice-counties,
+# Norwegian counties from after the 2018 and 2020 reforms. Matching those names
+# onto the nearest-looking GADM unit is worse than not matching them at all,
+# because the coordinate then falls in a different unit and a correctly
+# georeferenced, correctly labelled record looks geo-invalid.
+#
+# This component recognises such names as units in their own right. A unit with a
+# known EXTENT - the set of GADM units it covers - can be validated properly: the
+# coordinate must fall inside one of them. A unit whose extent has not been sourced
+# yet is UNVERIFIABLE: recognised, and never called invalid.
+#
+# Curation: data-raw/altdiv.R -> inst/extdata/altdiv_{units,names,extent}.csv.
+# ===========================================================================
+
+#' @keywords internal
+#' @noRd
+gnrs_altdiv_path <- function(table, dir = gnrs_cache_dir()) {
+  file.path(dir, paste0("altdiv-", table, ".gz.parquet"))
+}
+
+#' Build the alternative-division component
+#'
+#' Internal.  Reads the shipped curation and writes it to the cache.  No
+#' download.  When the GADM layer is present the extents are checked against it,
+#' so a unit can never claim a GADM division that does not exist.
+#' @keywords internal
+#' @noRd
+gnrs_build_altdiv <- function(dir = gnrs_cache_dir(create = TRUE), quiet = FALSE) {
+  if (!dir.exists(dir)) dir.create(dir, recursive = TRUE, showWarnings = FALSE)
+  rd <- function(f) utils::read.csv(gnrs_extdata(f), stringsAsFactors = FALSE,
+                                    encoding = "UTF-8", na.strings = "")
+  units <- rd("altdiv_units.csv")
+  names_ <- rd("altdiv_names.csv")
+  extent <- rd("altdiv_extent.csv")
+  units$valid_from <- as.Date(units$valid_from)
+  units$valid_to <- as.Date(units$valid_to)
+  if (anyDuplicated(units$entity_key)) stop("Alternative-division keys are not unique.", call. = FALSE)
+  stopifnot(all(names_$entity_key %in% units$entity_key),
+            all(extent$entity_key %in% units$entity_key))
+
+  known <- unique(extent$entity_key)
+  units$extent_known <- units$entity_key %in% known
+  if (nrow(extent) && gnrs_is_built("gadm", dir) && file.exists(gnrs_gadm_path(dir))) {
+    g <- as.data.frame(nanoparquet::read_parquet(gnrs_gadm_path(dir)))
+    have <- unique(c(g$gid_1, g$gid_2))
+    have <- have[!is.na(have)]
+    # only where the layer covers that country at all: a layer may be partial (and in
+    # the tests is synthetic), and an extent naming a country it does not carry is not
+    # an error. Within a country the layer does carry, an unknown unit is a typo.
+    country <- function(x) sub("[.].*", "", x)
+    covered <- unique(country(have))
+    check <- extent$gid[country(extent$gid) %in% covered]
+    bad <- setdiff(check, have)
+    if (length(bad)) {
+      stop("Alternative-division extents name GADM units that are not in the layer: ",
+           paste(utils::head(bad, 5), collapse = ", "), call. = FALSE)
+    }
+  }
+
+  w <- function(x, table) nanoparquet::write_parquet(x, gnrs_altdiv_path(table, dir), compression = "gzip")
+  w(units, "units"); w(names_, "names"); w(extent, "extent")
+  provenance <- list(
+    source = "altdiv", full_name = "Alternative and superseded sub-national divisions",
+    version = "1", downloaded = as.character(Sys.Date()),
+    n_units = nrow(units), n_with_extent = length(known), n_names = nrow(names_),
+    systems = paste(sort(unique(units$system)), collapse = ", "),
+    sources = "Curated for GNRS; Norwegian county reforms of 2018 and 2020; Swedish landskap, lappmarker and lan name forms; Watsonian vice-counties"
+  )
+  saveRDS(provenance, gnrs_provenance_path("altdiv", dir))
+  gnrs_env$altdiv <- NULL
+  if (!quiet) {
+    message("  ", nrow(units), " alternative or superseded divisions (", length(known),
+            " with a known extent), ", nrow(names_), " names")
+  }
+  invisible(provenance)
+}
+
+#' The alternative-division tables, cached for the session
+#' @keywords internal
+#' @noRd
+gnrs_altdiv <- function(dir = gnrs_cache_dir()) {
+  paths <- gnrs_altdiv_path(c("units", "names", "extent"), dir)
+  if (!all(file.exists(paths))) return(NULL)
+  # the cache is for this directory and these files: a call with another dir,
+  # or after a rebuild, reads afresh
+  stamp <- paste(normalizePath(dir, winslash = "/"), paste(file.mtime(paths), collapse = "|"))
+  if (!is.null(gnrs_env$altdiv) && identical(gnrs_env$altdiv_stamp, stamp)) return(gnrs_env$altdiv)
+  rd <- function(p) as.data.frame(nanoparquet::read_parquet(p))
+  a <- list(units = rd(paths[1]), names = rd(paths[2]), extent = rd(paths[3]))
+  a$units$valid_from <- as.Date(a$units$valid_from)
+  a$units$valid_to <- as.Date(a$units$valid_to)
+  a$names$lower <- gnrs_lower(a$names$name)
+  a$country_of <- a$units$country_iso[match(a$names$entity_key, a$units$entity_key)]
+  a$exact <- a$names$match == "exact"
+  # A name can belong to two units of different systems: "Skane" is a lan and a
+  # landskap, "Norrbotten" likewise. Prefer the one whose extent is known, so a
+  # coordinate can still be checked; the order here is what match() picks up.
+  ord <- order(!a$units$extent_known[match(a$names$entity_key, a$units$entity_key)])
+  a$names <- a$names[ord, , drop = FALSE]
+  a$country_of <- a$country_of[ord]
+  a$exact <- a$names$match == "exact"
+  a$key_exact <- paste(a$country_of[a$exact], a$names$lower[a$exact], sep = "\u001f")
+  gnrs_env$altdiv <- a
+  gnrs_env$altdiv_stamp <- stamp
+  a
+}
+
+#' Match declared division names against the alternative divisions
+#'
+#' Internal.  Vectorised.  \code{country_iso} and \code{name} are the declared
+#' country and the declared state or county; \code{dates} are the record dates,
+#' used only for units that existed over a period.
+#'
+#' @return data.frame with one row per input: \code{entity_key}, \code{system},
+#'   \code{kind}, \code{extent_known}, and \code{in_period} - NA when the unit has
+#'   no dates or the record has none, so that a caller can tell "outside its
+#'   period" from "no date to check".
+#' @keywords internal
+#' @noRd
+gnrs_altdiv_match <- function(country_iso, name, dates = NULL, dir = gnrs_cache_dir(),
+                              altdiv = NULL) {
+  n <- length(name)
+  out <- data.frame(entity_key = rep(NA_character_, n), system = NA_character_,
+                    kind = NA_character_, extent_known = NA, in_period = NA,
+                    stringsAsFactors = FALSE)
+  # `altdiv` lets a caller that already holds the tables (the resolver, through the
+  # backbone) skip the cache lookup
+  a <- if (!is.null(altdiv)) altdiv else gnrs_altdiv(dir)
+  if (is.null(a) || !n) return(out)
+  nm <- gnrs_lower(trimws(ifelse(is.na(name), "", name)))
+  cc <- toupper(ifelse(is.na(country_iso), "", country_iso))
+  hit <- match(paste(cc, nm, sep = "\u001f"), a$key_exact)
+  key <- ifelse(is.na(hit), NA_character_, a$names$entity_key[a$exact][hit])
+
+  # the regex systems (vice-counties are written "VC57 Derbyshire"), tried only where
+  # no exact name matched, and only against patterns registered for that country
+  rx <- which(!a$exact)
+  todo <- which(is.na(key) & nzchar(nm))
+  for (r in rx) {
+    if (!length(todo)) break
+    cand <- todo[cc[todo] == a$country_of[r]]
+    if (!length(cand)) next
+    ok <- grepl(a$names$name[r], name[cand], perl = TRUE)
+    key[cand[ok]] <- a$names$entity_key[r]
+    todo <- setdiff(todo, cand[ok])
+  }
+
+  i <- match(key, a$units$entity_key)
+  out$entity_key <- key
+  out$system <- a$units$system[i]
+  out$kind <- a$units$kind[i]
+  out$extent_known <- a$units$extent_known[i]
+  if (!is.null(dates)) {
+    from <- a$units$valid_from[i]
+    to <- a$units$valid_to[i]
+    d <- as.Date(dates)
+    # NA where there is nothing to check: no dates on the unit, or none on the record
+    out$in_period <- ifelse(is.na(d) | (is.na(from) & is.na(to)), NA,
+                            (is.na(from) | d >= from) & (is.na(to) | d <= to))
+  }
+  out
+}
+
+#' The GADM units an alternative division covers
+#'
+#' Internal.  Returns a character vector of GADM ids, empty when the extent of
+#' that unit has not been sourced.
+#' @keywords internal
+#' @noRd
+gnrs_altdiv_extent <- function(entity_key, dir = gnrs_cache_dir()) {
+  a <- gnrs_altdiv(dir)
+  if (is.null(a) || is.na(entity_key)) return(character(0))
+  a$extent$gid[a$extent$entity_key == entity_key]
+}
diff --git a/R/local_build.R b/R/local_build.R
index 070f470..e1ced9f 100644
--- a/R/local_build.R
+++ b/R/local_build.R
@@ -6,7 +6,7 @@
 #' is kept in the standard user cache directory, and can be removed again with
 #' \code{GNRS_local_remove()}.
 #'
-#' Two components are fetched by default, and two more can be added.
+#' Two components are fetched by default, and five more can be added.
 #' \code{"gnrs"} is the web service's own
 #' reference tables of countries, states/provinces and counties/parishes,
 #' fetched through its API in a few small requests: every political division it
@@ -49,13 +49,32 @@
 #' GeoNames places its points near an edge often enough.  Build it before
 #' \code{"gadm"} (the order is arranged whatever order is given).
 #'
+#' \code{"cshapes"} and \code{"history"} serve the historical modes of
+#' \code{GNRS_local()}.  The first is CShapes 2.0, the boundaries of every
+#' independent state and dependency from 1886 to 2019, read from the
+#' \code{cshapes} package when it is installed and otherwise downloaded from
+#' its publisher (about 60 MB; CC BY-NC-SA 4.0, so nothing derived from it
+#' ships with the package).  The second assembles the historical entities,
+#' their names, codes and lineage from tables shipped with the package and
+#' from CShapes, and prunes its names against the current name table, so it
+#' is built last and rebuilt whenever a component it draws on is rebuilt.
+#' Asking for \code{"history"} builds \code{"cshapes"} if it is missing.
+#'
 #' Each component is recorded with its version, so that results obtained locally
 #' can be cited as precisely as results from the web service.  Use
 #' \code{GNRS_local_status()} to see what has been built.
 #'
 #' @param sources Character vector of components to build: \code{"gnrs"},
-#'   \code{"geonames"} (the two defaults), \code{"points"} and
-#'   \code{"gadm"}.  The other components are layered on or filtered to the
+#'   \code{"geonames"} (the two defaults), \code{"points"}, \code{"gadm"},
+#'   and, for \code{GNRS_local()}'s historical modes, \code{"cshapes"} (the
+#'   CShapes 2.0 boundaries of former countries, from the \code{cshapes}
+#'   package when it is installed, otherwise a 60 MB download) and
+#'   \code{"altdiv"} (alternative and superseded sub-national divisions, from
+#'   curation shipped with the package: nothing is downloaded, and
+#'   \code{GNRS_local()} builds it on first use) and
+#'   \code{"history"} (the historical entities, names and lineage, assembled
+#'   from tables shipped with the package and from CShapes, which it builds if
+#'   it is missing).  The other components are layered on or filtered to the
 #'   service's tables, so \code{"gnrs"} is built first if it is missing
 #'   whatever is asked for.
 #' @param dir Cache directory. Defaults to the standard user cache location.
@@ -102,7 +121,10 @@ GNRS_local_build <- function(sources = c("gnrs", "geonames"),
     return(invisible(NULL))
   }
 
-  if (!"gnrs" %in% sources && !gnrs_is_built("gnrs", dir)) {
+  # CShapes and the alternative divisions stand alone; everything else is
+  # layered on or filtered to the service's tables
+  dependent <- setdiff(sources, c("cshapes", "altdiv"))
+  if (length(dependent) && !"gnrs" %in% sources && !gnrs_is_built("gnrs", dir)) {
     if (!quiet) {
       message("The other components are layered on the service's reference tables, so 'gnrs' is built first.")
     }
@@ -111,12 +133,20 @@ GNRS_local_build <- function(sources = c("gnrs", "geonames"),
   # The reference tables come first whatever order was given, then the
   # alternate names and the coordinates, then the GADM layer, whose linking
   # uses the alternate names and the coordinates when it has them
+  # The history component checks its names against the assembled name table, so it
+  # is built last; CShapes geometry is independent of the other components
+  history_wanted <- "history" %in% sources
+  cshapes_wanted <- "cshapes" %in% sources
+  altdiv_wanted <- "altdiv" %in% sources
   sources <- intersect(c("gnrs", "geonames", "points", "gadm"), sources)
 
   if (!dir.exists(dir)) {
     dir.create(dir, recursive = TRUE, showWarnings = FALSE)
   }
 
+  # the history component prunes its names against the assembled name table,
+  # so it is rebuilt when any component that table draws on was rebuilt here
+  dependency_rebuilt <- FALSE
   for (source in sources) {
     if (gnrs_is_built(source, dir) && !overwrite) {
       if (!quiet) message("Source '", source, "' is already built; skipping.")
@@ -136,6 +166,7 @@ GNRS_local_build <- function(sources = c("gnrs", "geonames"),
       next
     }
 
+    dependency_rebuilt <- TRUE
     if (source == "gnrs") {
       gnrs_build_reference(dir = dir, url = url, quiet = quiet)
     } else if (source == "gadm") {
@@ -159,6 +190,27 @@ GNRS_local_build <- function(sources = c("gnrs", "geonames"),
   if (gnrs_is_built("gnrs", dir)) {
     gnrs_assemble_names(dir = dir, quiet = quiet)
   }
+  # the history component is derived from CShapes at build time, so it needs CShapes
+  # built even when only "history" was asked for (without rebuilding an existing copy)
+  cshapes_rebuilt <- FALSE
+  if ((cshapes_wanted && (overwrite || !gnrs_is_built("cshapes", dir))) ||
+      (history_wanted && !gnrs_is_built("cshapes", dir))) {
+    gnrs_build_cshapes(dir = dir, quiet = quiet)
+    cshapes_rebuilt <- TRUE
+  }
+  # a history component already built is derived from the CShapes and the
+  # name table that were just replaced, so it is rebuilt with them
+  if ((history_wanted && (overwrite || !gnrs_is_built("history", dir))) ||
+      ((cshapes_rebuilt || dependency_rebuilt) && gnrs_is_built("history", dir))) {
+    if (!quiet) message("Building the history component ...")
+    gnrs_build_history(dir = dir, quiet = quiet)
+  }
+  # Alternative and superseded sub-national divisions: shipped curation, nothing
+  # downloaded and nothing derived from another component, so it stands alone.
+  if (altdiv_wanted && (overwrite || !gnrs_is_built("altdiv", dir))) {
+    if (!quiet) message("Building the alternative-division component ...")
+    gnrs_build_altdiv(dir = dir, quiet = quiet)
+  }
   gnrs_forget_backbone()
 
   status <- suppressMessages(GNRS_local_status(dir))
@@ -764,7 +816,8 @@ gnrs_assemble_names <- function(dir = gnrs_cache_dir(), quiet = FALSE) {
     is_geo <- tbl$is_geoname
 
     rows <- alt[alt$geonameid %in% ids[is_geo], , drop = FALSE]
-    out <- data.frame(id = rows$geonameid, name = rows$name, name_type = original, stringsAsFactors = FALSE)
+    # rep(): with no alternate names built there are no rows to recycle over
+    out <- data.frame(id = rows$geonameid, name = rows$name, name_type = rep(original, nrow(rows)), stringsAsFactors = FALSE)
     for (col in name_cols) {
       out <- rbind(out, data.frame(
         id = ids[is_geo], name = tbl[[col]][is_geo], name_type = original, stringsAsFactors = FALSE
diff --git a/R/local_cache.R b/R/local_cache.R
index c116695..d03ec66 100644
--- a/R/local_cache.R
+++ b/R/local_cache.R
@@ -85,6 +85,52 @@ gnrs_builtin_registry <- function() {
       download_mb = 195,
       disk_mb = 8
     ),
+    history = list(
+      source = "history",
+      full_name = "Historical political divisions (entities, names, lineage)",
+      publisher = "Botanical Information and Ecology Network",
+      url = "shipped with the package",
+      license = "Curated tables: package licence; names from GeoNames (CC BY 4.0), CShapes 2.0 (CC BY-NC-SA 4.0), Unicode CLDR, ISO 3166-3 (Debian iso-codes)",
+      citation = paste(
+        "Historical country entities, names and lineage compiled for GNRS from CShapes 2.0",
+        "(Schvitz et al. 2022, Journal of Conflict Resolution 66: 144-161), GeoNames, Unicode CLDR",
+        "and ISO 3166-3."
+      ),
+      # Built from tables shipped with the package; nothing is downloaded
+      download_mb = 0,
+      disk_mb = 1
+    ),
+    altdiv = list(
+      source = "altdiv",
+      full_name = "Alternative and superseded sub-national divisions",
+      publisher = "Botanical Information and Ecology Network",
+      url = "shipped with the package",
+      license = "Curated tables: package licence",
+      citation = paste(
+        "Alternative and superseded sub-national divisions compiled for GNRS:",
+        "Swedish landskap, lappmarker and lan name forms; Watsonian vice-counties of",
+        "Britain and Ireland; Norwegian counties of the 2018 and 2020 reforms."
+      ),
+      # Built from tables shipped with the package; nothing is downloaded
+      download_mb = 0,
+      disk_mb = 1
+    ),
+    cshapes = list(
+      source = "cshapes",
+      full_name = "CShapes 2.0 historical state boundaries",
+      publisher = "International Conflict Research, ETH Zurich",
+      version = "2.0",
+      url = "https://icr.ethz.ch/data/cshapes/CShapes-2.0.geojson",
+      license = "CC BY-NC-SA 4.0",
+      citation = paste(
+        "Schvitz G., Girardin L., Ruegger S., Weidmann N. B., Cederman L.-E. & Gleditsch K. S.",
+        "(2022). Mapping the International System, 1886-2019: The CShapes 2.0 Dataset.",
+        "Journal of Conflict Resolution 66(1): 144-161."
+      ),
+      # Read from the cshapes package when installed; otherwise the GeoJSON
+      download_mb = 60,
+      disk_mb = 25
+    ),
     points = list(
       source = "points",
       full_name = "GeoNames coordinates",
@@ -183,6 +229,10 @@ gnrs_is_built <- function(source, dir = gnrs_cache_dir()) {
     gadm = file.exists(gnrs_gadm_path(dir)),
     geonames = file.exists(gnrs_altnames_path(dir)),
     points = file.exists(gnrs_points_path(dir)),
+    # every table the resolver reads, so an interrupted build is rebuilt
+    history = all(file.exists(gnrs_history_path(c("entities", "names", "lineage", "periods"), dir))),
+    cshapes = file.exists(gnrs_cshapes_versions_path(dir)) && file.exists(gnrs_cshapes_geom_path(dir)),
+    altdiv = all(file.exists(gnrs_altdiv_path(c("units", "names", "extent"), dir))),
     FALSE
   )
 }
@@ -299,7 +349,9 @@ GNRS_local_status <- function(dir = gnrs_cache_dir()) {
 #' @param sources NULL, the default, removes everything.  Otherwise the
 #'   components to remove, for instance \code{"gadm"} to go back to resolving
 #'   against the service's own GADM identifiers; the reference tables are
-#'   rederived from what remains.
+#'   rederived from what remains, and a built \code{"history"} component is
+#'   rebuilt against them, or removed along with \code{"cshapes"}, which it
+#'   is derived from.
 #' @param ask Ask for confirmation before deleting? Defaults to TRUE in an
 #'   interactive session.
 #' @return TRUE if anything was removed, FALSE otherwise, invisibly.
@@ -353,9 +405,18 @@ GNRS_local_remove <- function(dir = gnrs_cache_dir(), sources = NULL, ask = inte
     unlink(files)
     for (s in sources) unlink(gnrs_provenance_path(s, dir))
     if ("gadm" %in% sources) unlink(gnrs_gadm_archive_path(dir))
+    # the history component is derived from CShapes and pruned against the
+    # name table: it goes with CShapes, and is rebuilt when a name source goes
+    if ("cshapes" %in% sources && !"history" %in% sources) {
+      unlink(gnrs_source_files("history", dir))
+      unlink(gnrs_provenance_path("history", dir))
+    }
     if (gnrs_is_built("gnrs", dir)) {
       gnrs_finalize_reference(dir, quiet = TRUE)
       gnrs_assemble_names(dir, quiet = TRUE)
+      if (any(c("gadm", "geonames") %in% sources) && gnrs_is_built("history", dir) && gnrs_is_built("cshapes", dir)) {
+        gnrs_build_history(dir = dir, quiet = TRUE)
+      }
     }
   }
   gnrs_forget_backbone()
diff --git a/R/local_history.R b/R/local_history.R
new file mode 100644
index 0000000..f7f4816
--- /dev/null
+++ b/R/local_history.R
@@ -0,0 +1,255 @@
+#' Historical political divisions: the CShapes component
+#'
+#' Internal.  Part of the time-versioned division reference shared by GNRS and
+#' GVS (dev_notes/03 and 04).  Either package can build it; the code here is kept
+#' identical in both.
+#'
+#' CShapes 2.0 (Schvitz et al. 2022) gives the borders of independent states and
+#' dependencies from 1886 to 2019, one row per country-period with start and end
+#' dates.  It codes STATES, not names: Gleditsch & Ward code 365 "Russia (Soviet
+#' Union)" runs from 1886 to 2019 in 24 periods, so the Russian Empire, the USSR
+#' and the Russian Federation share it.  Entities (the USSR as a named division)
+#' are assigned to periods by the crosswalk, not here.
+#'
+#' Licence: CC BY-NC-SA 4.0.  The data are read from the `cshapes` package when
+#' it is installed, otherwise downloaded on the user's machine; nothing derived is
+#' shipped with the package.
+#' @keywords internal
+#' @noRd
+gnrs_cshapes_spec <- function() {
+  list(
+    source = "cshapes",
+    full_name = "CShapes 2.0 historical state boundaries",
+    publisher = "International Conflict Research, ETH Zurich",
+    version = "2.0",
+    url = "https://icr.ethz.ch/data/cshapes/CShapes-2.0.geojson",
+    license = "CC BY-NC-SA 4.0",
+    citation = paste(
+      "Schvitz G., Girardin L., Ruegger S., Weidmann N. B., Cederman L.-E. &",
+      "Gleditsch K. S. (2022). Mapping the International System, 1886-2019:",
+      "The CShapes 2.0 Dataset. Journal of Conflict Resolution 66(1): 144-161.",
+      "https://doi.org/10.1177/00220027211013563"
+    ),
+    download_mb = 60,
+    disk_mb = 25
+  )
+}
+
+#' @keywords internal
+#' @noRd
+gnrs_cshapes_versions_path <- function(dir = gnrs_cache_dir()) {
+  file.path(dir, "cshapes-versions.gz.parquet")
+}
+
+#' @keywords internal
+#' @noRd
+gnrs_cshapes_geom_path <- function(dir = gnrs_cache_dir()) {
+  file.path(dir, "cshapes-geometry.gpkg")
+}
+
+#' Read CShapes 2.0 as sf, from the cshapes package or the publisher
+#' @keywords internal
+#' @noRd
+gnrs_read_cshapes <- function(dir = gnrs_cache_dir(), quiet = FALSE) {
+  if (requireNamespace("cshapes", quietly = TRUE)) {
+    if (!quiet) message("Reading CShapes 2.0 from the cshapes package ...")
+    return(cshapes::cshp(date = NA, useGW = TRUE, dependencies = TRUE))
+  }
+  spec <- gnrs_cshapes_spec()
+  f <- file.path(dir, "cshapes-2.0.geojson")
+  if (!file.exists(f)) {
+    if (!quiet) message("Downloading ", spec$full_name, " (about ", spec$download_mb, " MB) ...")
+    partial <- paste0(f, ".part")
+    # R's default of 60 seconds is not enough for a file this size
+    old <- options(timeout = max(3600, getOption("timeout")))
+    on.exit(options(old), add = TRUE)
+    status <- utils::download.file(spec$url, partial, mode = "wb", quiet = quiet, cacheOK = FALSE)
+    if (status != 0 || !file.exists(partial)) {
+      unlink(partial)
+      stop("Download failed for CShapes.", call. = FALSE)
+    }
+    if (!file.rename(partial, f)) {
+      unlink(partial)
+      stop("Could not move the downloaded CShapes file into place.", call. = FALSE)
+    }
+  }
+  x <- sf::st_read(f, quiet = TRUE)
+  # the geojson spells the Gleditsch & Ward code and dates like the package does
+  x$start <- as.Date(x$gwsdate %||% x$start)
+  x$end <- as.Date(x$gwedate %||% x$end)
+  x
+}
+
+#' Build the CShapes component: one row per country-period, with its six centroids
+#'
+#' Internal.  Writes
+#' \itemize{
+#'   \item \code{cshapes-versions.gz.parquet}: version_id, gwcode, country_name,
+#'     valid_from, valid_to, status, owner, capital name and coordinates, b_def,
+#'     area_km2, and the six planar centroids with their maximum distances
+#'     (\code{c1_lon} ... \code{c6_dmax}), exactly as GVS computes them for GADM;
+#'   \item \code{cshapes-geometry.gpkg}: the polygons, keyed by version_id.
+#' }
+#' @keywords internal
+#' @noRd
+gnrs_build_cshapes <- function(dir = gnrs_cache_dir(create = TRUE), quiet = FALSE) {
+  for (pkg in c("sf", "nanoparquet")) {
+    if (!requireNamespace(pkg, quietly = TRUE)) {
+      stop("Building the CShapes component needs the '", pkg, "' package.", call. = FALSE)
+    }
+  }
+  x <- gnrs_read_cshapes(dir = dir, quiet = quiet)
+  n <- nrow(x)
+  version_id <- sprintf("cshapes:%d:%s", as.integer(x$gwcode), format(as.Date(x$start)))
+  if (anyDuplicated(version_id)) stop("CShapes version ids are not unique.", call. = FALSE)
+
+  old_s2 <- sf::sf_use_s2()
+  on.exit(suppressMessages(sf::sf_use_s2(old_s2)), add = TRUE)
+  # Repair with GEOS, not s2: s2's st_make_valid re-expresses polygons that cross the
+  # antimeridian with longitudes beyond 180 (Russia's planar centroid came out at
+  # 214.8 degrees instead of 96.8), which breaks point-in-polygon and the planar
+  # centroids GVS compares against GADM.  s2 also rejects some unrepaired CShapes
+  # rings (degenerate edges), and an ellipsoidal area with s2 off would need the
+  # lwgeom package, so the area is taken in an equal-area projection with planar
+  # geometry, which needs only PROJ.  Long straight edges in longitude/latitude
+  # (the 129th meridian between Western and South Australia has two vertices)
+  # are densified first, since a chord between distant vertices cuts area off
+  # one side and adds it to the other once projected; the cylindrical equal-area
+  # projection keeps meridians and parallels straight and gives the ellipsoidal
+  # area.  Checked against lwgeom's ellipsoidal area over all 710 CShapes
+  # country-periods: median ratio 1.0000, 99 percent within 0.1 percent, the
+  # worst 0.4 percent (a diagonal border treated as a rhumb line, not a geodesic).
+  suppressMessages(sf::sf_use_s2(FALSE))
+  x <- sf::st_make_valid(x)
+  area_km2 <- gnrs_equal_area_km2(sf::st_geometry(x))
+  bb <- sf::st_bbox(x)
+  if (bb[["xmin"]] < -180 || bb[["xmax"]] > 180 || bb[["ymin"]] < -90 || bb[["ymax"]] > 90) {
+    stop("CShapes geometry outside WGS84 longitude/latitude bounds after repair.", call. = FALSE)
+  }
+
+  if (!quiet) message("Deriving centroids for ", n, " country-periods ...")
+  cents <- gnrs_six_centroids(sf::st_geometry(x))
+
+  attrs <- sf::st_drop_geometry(x)
+  versions <- data.frame(
+    version_id = version_id,
+    gwcode = as.integer(attrs$gwcode),
+    country_name = attrs$country_name,
+    valid_from = as.Date(attrs$start),
+    valid_to = as.Date(attrs$end),
+    status = attrs$status,
+    owner = suppressWarnings(as.integer(attrs$owner)),
+    capital = attrs$capname,
+    capital_lon = attrs$caplong,
+    capital_lat = attrs$caplat,
+    border_defined = as.integer(attrs$b_def),
+    area_km2 = round(area_km2, 1),
+    stringsAsFactors = FALSE
+  )
+  versions <- cbind(versions, cents)
+  nanoparquet::write_parquet(versions, gnrs_cshapes_versions_path(dir), compression = "gzip")
+
+  g <- sf::st_sf(version_id = version_id, geometry = sf::st_geometry(x))
+  unlink(gnrs_cshapes_geom_path(dir))
+  sf::st_write(g, gnrs_cshapes_geom_path(dir), layer = "country", quiet = TRUE)
+
+  spec <- gnrs_cshapes_spec()
+  provenance <- list(
+    source = spec$source, full_name = spec$full_name, version = spec$version,
+    url = spec$url, license = spec$license, citation = spec$citation,
+    downloaded = as.character(Sys.Date()),
+    via = if (requireNamespace("cshapes", quietly = TRUE)) {
+      paste("cshapes package", as.character(utils::packageVersion("cshapes")))
+    } else {
+      "publisher download"
+    },
+    n_versions = n,
+    n_states = length(unique(versions$gwcode)),
+    first_date = as.character(min(versions$valid_from)),
+    last_date = as.character(max(versions$valid_to))
+  )
+  saveRDS(provenance, gnrs_provenance_path("cshapes", dir))
+  if (!quiet) {
+    message("  ", n, " country-periods of ", provenance$n_states, " states, ",
+            provenance$first_date, " to ", provenance$last_date)
+  }
+  invisible(provenance)
+}
+
+#' The six GVS centroids of each (multi)polygon
+#'
+#' Internal.  Identical to RGVS's \code{gvs_six_centroids()}: centre of mass,
+#' point on surface and bounding-box centre, for the whole division and for its
+#' largest part, each with the greatest planar distance from it to the WHOLE
+#' division's vertices.  Planar WGS84 throughout, including across the
+#' antimeridian, deliberately: GVS detects centroids that users computed naively.
+#' @keywords internal
+#' @noRd
+gnrs_six_centroids <- function(geom) {
+  n <- length(geom)
+  out <- matrix(NA_real_, n, 18)
+  main <- gnrs_largest_part(geom)
+  for (half in 1:2) {
+    g <- if (half == 1) geom else main
+    cent <- suppressWarnings(sf::st_coordinates(sf::st_centroid(g)))
+    pos <- suppressWarnings(sf::st_coordinates(sf::st_point_on_surface(g)))
+    bb <- vapply(g, function(x) {
+      b <- sf::st_bbox(x)
+      c((b[["xmin"]] + b[["xmax"]]) / 2, (b[["ymin"]] + b[["ymax"]]) / 2)
+    }, numeric(2))
+    types <- list(cent[, 1:2, drop = FALSE], pos[, 1:2, drop = FALSE], t(bb))
+    for (k in seq_along(types)) {
+      col <- (half - 1) * 9 + (k - 1) * 3 + 1
+      out[, col] <- types[[k]][, 1]
+      out[, col + 1] <- types[[k]][, 2]
+      out[, col + 2] <- gnrs_max_vertex_distance(geom, types[[k]])
+    }
+  }
+  colnames(out) <- paste0("c", rep(1:6, each = 3), c("_lon", "_lat", "_dmax"))
+  as.data.frame(out)
+}
+
+#' @keywords internal
+#' @noRd
+gnrs_largest_part <- function(geom) {
+  parts <- lapply(geom, function(g) {
+    pieces <- suppressWarnings(sf::st_cast(sf::st_sfc(g), "POLYGON"))
+    if (length(pieces) <= 1) {
+      return(g)
+    }
+    areas <- suppressWarnings(as.numeric(sf::st_area(sf::st_set_crs(pieces, NA))))
+    pieces[[which.max(areas)]]
+  })
+  sf::st_sfc(parts, crs = sf::st_crs(geom))
+}
+
+#' @keywords internal
+#' @noRd
+gnrs_max_vertex_distance <- function(geom, centres) {
+  vapply(seq_along(geom), function(i) {
+    xy <- sf::st_coordinates(sf::st_sfc(geom[[i]]))
+    if (!nrow(xy) || any(is.na(centres[i, ]))) {
+      return(NA_real_)
+    }
+    max(sqrt((xy[, 1] - centres[i, 1])^2 + (xy[, 2] - centres[i, 2])^2))
+  }, numeric(1))
+}
+
+#' Area of longitude/latitude polygons without s2 or lwgeom
+#'
+#' Internal.  Planar densification of the edges (every 0.05 degrees, about
+#' 5 km), then the cylindrical equal-area projection on the WGS84 ellipsoid
+#' (EPSG:6933) and a planar area.  Used where s2 is switched off and the
+#' lwgeom package cannot be assumed.
+#'
+#' @param geometry An sfc of polygons in longitude/latitude.
+#' @return Areas in square kilometres.
+#' @keywords internal
+#' @noRd
+gnrs_equal_area_km2 <- function(geometry) {
+  planar <- sf::st_set_crs(geometry, NA)
+  dense <- sf::st_segmentize(planar, 0.05)
+  dense <- sf::st_set_crs(dense, 4326)
+  projected <- sf::st_transform(dense, "EPSG:6933")
+  as.numeric(sf::st_area(projected)) / 1e6
+}
diff --git a/R/local_history_assemble.R b/R/local_history_assemble.R
new file mode 100644
index 0000000..f2c0ab6
--- /dev/null
+++ b/R/local_history_assemble.R
@@ -0,0 +1,271 @@
+# ===========================================================================
+# Assembling the history tables at build time
+#
+# CShapes 2.0 is CC BY-NC-SA 4.0 and this package is MIT, so nothing derived from
+# CShapes ships with it (BM, 2026-09-22). The package carries only the curation
+# (inst/extdata, from data-raw/history_crosswalk.R) and extracts from
+# redistributable sources. Everything that depends on CShapes - the periods of
+# every state code the curation does not assign, the synthetic CSH<gwcode>
+# entities and their names, the coverage check, and the lineage derived from
+# CShapes geometry - is computed here from the user's own copy of CShapes, which
+# GNRS_local_build("cshapes") puts in the cache.
+#
+# This reproduces what data-raw/history_crosswalk.R computed before 2026-09-22
+# step for step; the test suite checks the result against those tables.
+# ===========================================================================
+
+#' Minimum share of a predecessor's area a successor must receive to be linked
+#' @keywords internal
+#' @noRd
+gnrs_history_min_share <- function() 0.05
+
+#' Days after a predecessor ends within which a successor may first appear
+#'
+#' Successor states often appear weeks after the predecessor ends
+#' (Austria-Hungary ended 1918-11-02; Czechoslovakia starts 1918-11-11).
+#' @keywords internal
+#' @noRd
+gnrs_history_window_days <- function() 365
+
+#' Names kept out of fuzzy matching
+#'
+#' Short former names that are prefixes or near-duplicates of other entities'
+#' names ("Rhodesia": "N. Rhodesia", which is Zambia, fuzzy-matched it).
+#' @keywords internal
+#' @noRd
+gnrs_history_exact_only_names <- function() c("Rhodesia")
+
+#' Assemble the history tables from the curation and the cached CShapes
+#'
+#' Internal.  Returns a list of data frames - \code{ent}, \code{nm}, \code{lin},
+#' \code{per}, \code{codes} - with the columns and types of the tables that
+#' previously shipped in inst/extdata, so \code{gnrs_build_history()} treats them
+#' exactly as it treated those.
+#' @keywords internal
+#' @noRd
+gnrs_history_assemble <- function(dir = gnrs_cache_dir(), quiet = FALSE) {
+  for (pkg in c("sf", "countrycode")) {
+    if (!requireNamespace(pkg, quietly = TRUE)) {
+      stop("Building the history component needs the '", pkg, "' package.", call. = FALSE)
+    }
+  }
+  if (!file.exists(gnrs_cshapes_versions_path(dir)) || !file.exists(gnrs_cshapes_geom_path(dir))) {
+    stop("The history component is derived from CShapes, which has not been built. ",
+         "Run GNRS_local_build(\"cshapes\").", call. = FALSE)
+  }
+  # Only empty cells are missing: "NA" is Namibia's ISO code
+  rd <- function(f) utils::read.csv(gnrs_extdata(f), stringsAsFactors = FALSE, encoding = "UTF-8",
+                                    na.strings = "", colClasses = "character")
+  num <- function(x) as.integer(x)
+  day <- function(x) as.Date(x)
+
+  # ---- current entities: the snapshot shipped with the curation ---------------
+  # Fixed with the curation, as it always was: which uncurated state codes map to a
+  # current country depends on this list, so it must not drift with the user's backbone.
+  cur <- rd("history_current_entities.csv")
+  cur$valid_from <- day(cur$valid_from)
+  cur$valid_to <- day(cur$valid_to)
+
+  # ---- curated historical entities -------------------------------------------
+  hist <- rd("history_curated_entities.csv")
+  hist$valid_from <- day(hist$valid_from)
+  hist$valid_to <- day(hist$valid_to)
+
+  # ---- CShapes, from the cache -------------------------------------------------
+  csd <- as.data.frame(nanoparquet::read_parquet(gnrs_cshapes_versions_path(dir)))
+  csd <- data.frame(version_id = csd$version_id, gwcode = as.integer(csd$gwcode),
+                    country_name = csd$country_name, start = day(csd$valid_from),
+                    end = day(csd$valid_to), stringsAsFactors = FALSE)
+  by_gw <- split(seq_len(nrow(csd)), csd$gwcode)
+  g <- data.frame(
+    gwcode = as.integer(names(by_gw)),
+    first = as.Date(vapply(by_gw, function(i) as.numeric(min(csd$start[i])), numeric(1)), origin = "1970-01-01"),
+    last = as.Date(vapply(by_gw, function(i) as.numeric(max(csd$end[i])), numeric(1)), origin = "1970-01-01"),
+    cs_name = vapply(by_gw, function(i) csd$country_name[i][which.max(csd$end[i])], character(1)),
+    stringsAsFactors = FALSE
+  )
+  g$iso2 <- suppressWarnings(countrycode::countrycode(g$gwcode, "gwn", "iso2c", warn = FALSE))
+
+  # ---- state code -> entity over periods ---------------------------------------
+  # curated assignments; every other code follows countrycode when it gives a current
+  # country, else becomes a synthetic entity CSH<gwcode>
+  cp <- rd("history_curated_periods.csv")
+  curated_periods <- data.frame(gwcode = num(cp$gwcode), from = day(cp$from), to = day(cp$to),
+                                entity_key = cp$entity_key, note = cp$note, basis = cp$basis,
+                                stringsAsFactors = FALSE)
+  auto <- g[!g$gwcode %in% curated_periods$gwcode, , drop = FALSE]
+  auto$entity_key <- ifelse(!is.na(auto$iso2) & auto$iso2 %in% cur$entity_key, auto$iso2,
+                            paste0("CSH", auto$gwcode))
+  syn <- startsWith(auto$entity_key, "CSH")
+  auto_periods <- data.frame(gwcode = auto$gwcode, from = auto$first, to = auto$last,
+                             entity_key = auto$entity_key,
+                             note = ifelse(syn, paste("synthetic entity:", auto$cs_name), NA_character_),
+                             basis = ifelse(syn, "synthetic", "countrycode gwn->iso2c"),
+                             stringsAsFactors = FALSE)
+  periods <- rbind(curated_periods, auto_periods)
+  periods <- periods[order(periods$gwcode, periods$from), , drop = FALSE]
+
+  # every other CShapes state without a current country is a synthetic historical
+  # entity, named as CShapes names it (colonies, protectorates, former states)
+  synth <- data.frame(entity_key = auto$entity_key[syn], name = auto$cs_name[syn],
+                      geonameid = NA_character_, iso3166_1 = NA_character_, iso3166_3 = NA_character_,
+                      valid_from = auto$first[syn], valid_to = auto$last[syn], kind = "historical",
+                      note = "synthetic entity from a CShapes state with no current country",
+                      stringsAsFactors = FALSE)
+  entities <- rbind(cur, hist, synth)
+  if (anyDuplicated(entities$entity_key)) stop("History entity keys are not unique.", call. = FALSE)
+  missing_ent <- setdiff(periods$entity_key, entities$entity_key)
+  if (length(missing_ent)) {
+    stop("History periods reference unknown entities: ", paste(missing_ent, collapse = ", "), call. = FALSE)
+  }
+
+  # every CShapes version must be covered by an entity period on the days it is valid
+  covered <- vapply(seq_len(nrow(csd)), function(i) {
+    any(periods$gwcode == csd$gwcode[i] & periods$from <= csd$end[i] & periods$to >= csd$start[i])
+  }, logical(1))
+  if (!all(covered)) {
+    stop("CShapes versions not covered by any entity period: ",
+         paste(csd$version_id[!covered], collapse = ", "), call. = FALSE)
+  }
+
+  # ---- lineage ---------------------------------------------------------------------
+  cl <- rd("history_curated_lineage.csv")
+  lin <- data.frame(from_entity = cl$from_entity, to_entity = cl$to_entity, relation = cl$relation,
+                    date = day(cl$date), source = cl$source, stringsAsFactors = FALSE)
+  geo_lin <- gnrs_history_geometry_lineage(dir, csd, periods, entities, lin, quiet = quiet)
+  lin <- rbind(lin, geo_lin)
+  bad <- setdiff(c(lin$from_entity, lin$to_entity), entities$entity_key)
+  if (length(bad)) stop("History lineage references unknown entities: ", paste(bad, collapse = ", "), call. = FALSE)
+
+  # ---- former codes -> entity -------------------------------------------------------
+  codes <- rd("history_codes.csv")
+  codes <- codes[codes$entity_key %in% entities$entity_key, , drop = FALSE]
+
+  # ---- names -------------------------------------------------------------------------
+  # Names by which records refer to an entity, each with its source. The order of the
+  # sources matters: where two give the same name, the first keeps it.
+  hist_keys <- entities$entity_key[entities$kind == "historical"]
+  ent_names <- data.frame(entity_key = hist_keys, name = entities$name[entities$kind == "historical"],
+                          source = "entity name", stringsAsFactors = FALSE)
+  curated_names <- rd("history_curated_names.csv")[, c("entity_key", "name", "source")]
+  cs_names <- merge(periods[, c("gwcode", "entity_key")],
+                    data.frame(gwcode = csd$gwcode, name = csd$country_name, stringsAsFactors = FALSE),
+                    by = "gwcode")
+  cs_names <- cs_names[cs_names$entity_key %in% hist_keys, c("entity_key", "name")]
+  cs_names$source <- "CShapes 2.0"
+  cs_names <- unique(cs_names)
+  gn <- rd("history_geonames_names.csv")
+  gn_names <- merge(gn, entities[!is.na(entities$geonameid), c("geonameid", "entity_key")], by = "geonameid")
+  gn_names <- gn_names[nzchar(gn_names$name), c("entity_key", "name")]
+  gn_names$source <- "GeoNames (CC BY 4.0)"
+  # the former codes themselves ("SUHH", "ANHH"), which a record may carry in place
+  # of a name, and the names ISO lists them under
+  iso_codes <- unique(data.frame(entity_key = codes$entity_key, name = codes$code, source = "ISO 3166-3",
+                                 stringsAsFactors = FALSE))
+  iso_names <- unique(data.frame(entity_key = codes$entity_key, name = codes$name, source = "ISO 3166-3 name",
+                                 stringsAsFactors = FALSE))
+  hnames <- rbind(ent_names, curated_names, cs_names, gn_names, iso_codes, iso_names)
+  hnames <- hnames[!duplicated(hnames[, c("entity_key", "name")]), , drop = FALSE]
+  hnames <- hnames[nzchar(trimws(hnames$name)), , drop = FALSE]
+  # fuzzy: may this name take part in GNRS fuzzy matching? Exact-only for names of
+  # synthetic entities made from CShapes colonies (obscure names that drew fuzzy matches
+  # from current countries on GBIF data: "Northern Rhodesia> Zambia" -> "Northeastern
+  # Rhodesia") and for short former names that are near-duplicates of other entities'
+  # ... and never for a code, which is matched whole or not at all
+  hnames$fuzzy <- !grepl("^CSH[0-9]+$", hnames$entity_key) &
+    !(hnames$name %in% gnrs_history_exact_only_names()) &
+    hnames$source != "ISO 3166-3"
+  bad <- setdiff(hnames$entity_key, entities$entity_key)
+  if (length(bad)) stop("History names reference unknown entities: ", paste(bad, collapse = ", "), call. = FALSE)
+
+  if (!quiet) {
+    message("  from CShapes: ", nrow(synth), " synthetic entities, ", sum(periods$basis != "curated"),
+            " uncurated state-code periods, ", nrow(geo_lin), " geometry-derived lineage links")
+  }
+  lapply(list(ent = entities, nm = hnames, lin = lin, per = periods, codes = codes), gnrs_csv_types)
+}
+
+#' Successors of historical entities without curated lineage, from CShapes geometry
+#'
+#' Internal.  Mostly CShapes colonies and protectorates: the entity's last polygon
+#' is intersected with the CShapes versions valid on the day after it ends, or, for
+#' states with no such version, their first version starting within
+#' \code{gnrs_history_window_days()}; every successor receiving at least
+#' \code{gnrs_history_min_share()} of its area is linked. Shares are planar in
+#' degrees, adequate for apportioning one territory among neighbours. Geometry is
+#' used here only.
+#' @keywords internal
+#' @noRd
+gnrs_history_geometry_lineage <- function(dir, csd, periods, entities, lin, quiet = FALSE) {
+  min_share <- gnrs_history_min_share()
+  window <- gnrs_history_window_days()
+  old_s2 <- sf::sf_use_s2()
+  on.exit(suppressMessages(sf::sf_use_s2(old_s2)), add = TRUE)
+  suppressMessages(sf::sf_use_s2(FALSE))
+
+  cs <- sf::st_read(gnrs_cshapes_geom_path(dir), layer = "country", quiet = TRUE)
+  m <- match(cs$version_id, csd$version_id)
+  if (anyNA(m)) stop("CShapes geometry and versions disagree; rebuild the CShapes component.", call. = FALSE)
+  cs$gwcode <- csd$gwcode[m]
+  cs$start <- csd$start[m]
+  cs$end <- csd$end[m]
+
+  ent_of <- function(gw, d) {
+    hit <- periods$entity_key[periods$gwcode == gw & periods$from <= d & periods$to >= d]
+    if (length(hit)) hit[1] else NA_character_
+  }
+  need <- setdiff(entities$entity_key[entities$kind == "historical"], lin$from_entity)
+  out <- list()
+  for (ek in need) {
+    pr <- periods[periods$entity_key == ek, , drop = FALSE]
+    if (!nrow(pr)) next
+    last_day <- max(pr$to)
+    if (last_day >= as.Date("2019-12-31")) next
+    last_v <- cs[cs$gwcode %in% pr$gwcode & cs$start <= last_day & cs$end >= last_day, ]
+    if (!nrow(last_v)) next
+    # planar on purpose (see above); sf says so on every call, so it is silenced
+    pred <- suppressMessages(sf::st_union(sf::st_make_valid(sf::st_geometry(last_v))))
+    a0 <- as.numeric(sf::st_area(sf::st_set_crs(pred, NA)))
+    on_day <- cs$start <= last_day + 1 & cs$end >= last_day + 1
+    soon <- cs$start > last_day + 1 & cs$start <= last_day + window & !(cs$gwcode %in% cs$gwcode[on_day])
+    nxt <- cs[on_day | soon, ]
+    nxt <- nxt[order(nxt$gwcode, nxt$start), ]
+    nxt <- nxt[!duplicated(nxt$gwcode), ]
+    nxt <- nxt[lengths(suppressMessages(sf::st_intersects(nxt, pred))) > 0, ]
+    if (!nrow(nxt)) next
+    inter <- suppressMessages(suppressWarnings(sf::st_intersection(sf::st_make_valid(sf::st_geometry(nxt)), pred)))
+    share <- as.numeric(sf::st_area(sf::st_set_crs(inter, NA))) / a0
+    keep <- share >= min_share
+    if (!any(keep)) next
+    gw <- nxt$gwcode[keep]
+    d <- pmax(last_day + 1, nxt$start[keep])
+    to <- vapply(seq_along(gw), function(i) ent_of(gw[i], d[i]), character(1))
+    ok <- !is.na(to) & to != ek
+    if (!any(ok)) next
+    s <- tapply(share[keep][ok], factor(to[ok], levels = unique(to[ok])), sum)
+    out[[ek]] <- data.frame(from_entity = ek, to_entity = names(s), relation = "territory_to",
+                            date = last_day + 1, source = sprintf("CShapes geometry overlap (share %.2f)", as.numeric(s)),
+                            stringsAsFactors = FALSE)
+  }
+  if (!length(out)) {
+    return(data.frame(from_entity = character(0), to_entity = character(0), relation = character(0),
+                      date = as.Date(character(0)), source = character(0), stringsAsFactors = FALSE))
+  }
+  do.call(rbind, unname(out))
+}
+
+#' Give a table the column types it would have if read back from CSV
+#'
+#' Internal.  gnrs_build_history() was written against tables read from shipped
+#' CSVs (dates and codes as text, identifiers as integers); a round trip through a
+#' temporary CSV reproduces those types exactly, so the cache is unchanged by the
+#' move from shipped tables to tables assembled at build time.
+#' @keywords internal
+#' @noRd
+gnrs_csv_types <- function(x) {
+  f <- tempfile(fileext = ".csv")
+  on.exit(unlink(f), add = TRUE)
+  for (j in seq_along(x)) if (inherits(x[[j]], "Date")) x[[j]] <- format(x[[j]])
+  utils::write.csv(x, f, row.names = FALSE, na = "", fileEncoding = "UTF-8")
+  utils::read.csv(f, stringsAsFactors = FALSE, encoding = "UTF-8", na.strings = "")
+}
diff --git a/R/local_history_resolve.R b/R/local_history_resolve.R
new file mode 100644
index 0000000..9ead466
--- /dev/null
+++ b/R/local_history_resolve.R
@@ -0,0 +1,415 @@
+# ===========================================================================
+# The history component: entities, names, lineage, CShapes periods and former
+# codes, assembled at build time from the curation shipped in inst/extdata
+# (data-raw/history_crosswalk.R) and the user's cached CShapes
+# (gnrs_history_assemble(), R/local_history_assemble.R), and resolution against them.
+# ===========================================================================
+
+#' Path of a shipped history table
+#'
+#' Internal.  In an installed package these are under inst/extdata; while
+#' developing from source, set \code{options(GNRS.extdata_dir = )}.
+#' @keywords internal
+#' @noRd
+gnrs_extdata <- function(file) {
+  dev <- getOption("GNRS.extdata_dir")
+  if (!is.null(dev)) {
+    return(file.path(dev, file))
+  }
+  path <- system.file("extdata", file, package = "GNRS")
+  if (!nzchar(path)) stop("History table not found in the package: ", file, call. = FALSE)
+  path
+}
+
+#' @keywords internal
+#' @noRd
+gnrs_history_path <- function(table, dir = gnrs_cache_dir()) {
+  file.path(dir, paste0("history-", table, ".gz.parquet"))
+}
+
+#' First identifier of the range reserved for entities without a GeoNames id
+#'
+#' GeoNames identifiers are below 13 million; the reserved range starts well above.
+#' @keywords internal
+#' @noRd
+gnrs_history_synthetic_base <- function() 990000000L
+
+#' Build the history component
+#'
+#' Internal.  Assembles the tables (gnrs_history_assemble()), gives every entity a numeric identifier
+#' (its GeoNames id where it has one, so results join to GeoNames and to the web
+#' service; otherwise one in a reserved range, stable across builds because it is
+#' assigned in order of entity key), and writes them to the cache.  No download,
+#' but it needs the CShapes component built first.
+#'
+#' Names that collide with a CURRENT country's standard or alternate name are
+#' handled so that a current country wins ties: a colliding name from a
+#' non-curated source is dropped; a colliding curated name is kept and reported,
+#' because it was added deliberately.
+#' @keywords internal
+#' @noRd
+gnrs_build_history <- function(dir = gnrs_cache_dir(create = TRUE), quiet = FALSE) {
+  # Nothing derived from CShapes ships (it is CC BY-NC-SA 4.0; the package is MIT):
+  # the tables are assembled here from the curation and the user's cached CShapes.
+  h <- gnrs_history_assemble(dir = dir, quiet = quiet)
+  ent <- h$ent
+  nm <- h$nm
+  lin <- h$lin
+  per <- h$per
+  codes <- h$codes
+
+  synth <- sort(ent$entity_key[is.na(ent$geonameid)])
+  ent$entity_id <- suppressWarnings(as.integer(ent$geonameid))
+  no_id <- is.na(ent$entity_id)
+  ent$entity_id[no_id] <- gnrs_history_synthetic_base() + match(ent$entity_key[no_id], synth)
+  if (anyDuplicated(ent$entity_id)) stop("History entity identifiers are not unique.", call. = FALSE)
+  ent$short_name <- sub(" \\(.*\\)$", "", ent$name)
+  id_of <- function(k) ent$entity_id[match(k, ent$entity_key)]
+
+  nm$entity_id <- id_of(nm$entity_key)
+  lin$from_id <- id_of(lin$from_entity)
+  lin$to_id <- id_of(lin$to_entity)
+  per$entity_id <- id_of(per$entity_key)
+  codes$entity_id <- id_of(codes$entity_key)
+
+  # collisions with current country names (standard and GeoNames alternate)
+  collisions <- data.frame(entity_key = character(0), name = character(0),
+                           source = character(0), current_country_id = integer(0))
+  if (gnrs_is_built("gnrs", dir)) {
+    cur_country <- as.data.frame(nanoparquet::read_parquet(gnrs_reference_path("country", dir)))
+    cur_names <- data.frame(id = integer(0), name = character(0))
+    if (file.exists(gnrs_names_path(dir))) {
+      x <- as.data.frame(nanoparquet::read_parquet(gnrs_names_path(dir)))
+      cur_names <- x[x$level == "country", c("id", "name"), drop = FALSE]
+    }
+    current_lower <- gnrs_lower(c(cur_country$country, cur_names$name))
+    current_id <- c(cur_country$country_id, cur_names$id)
+    hit <- match(gnrs_lower(nm$name), current_lower)
+    clash <- !is.na(hit) & current_id[hit] != nm$entity_id
+    if (any(clash)) {
+      collisions <- nm[clash, c("entity_key", "name", "source")]
+      collisions$current_country_id <- current_id[hit[clash]]
+    }
+    drop <- clash & nm$source != "curated"
+    nm <- nm[!drop, , drop = FALSE]
+    if (!quiet && any(clash)) {
+      message("  ", sum(drop), " historical names dropped because a current country has the same name; ",
+              sum(clash & !drop), " curated collisions kept (see history-collisions)")
+    }
+  }
+
+  w <- function(x, table) nanoparquet::write_parquet(x, gnrs_history_path(table, dir), compression = "gzip")
+  w(ent, "entities")
+  w(nm, "names")
+  w(lin, "lineage")
+  w(per, "periods")
+  w(codes, "codes")
+  w(collisions, "collisions")
+
+  provenance <- list(
+    source = "history", full_name = "Historical political divisions (entities, names, lineage)",
+    version = "1", downloaded = as.character(Sys.Date()),
+    n_entities = nrow(ent), n_historical = sum(ent$kind == "historical"),
+    n_names = nrow(nm), n_lineage = nrow(lin), n_periods = nrow(per),
+    sources = paste("Curated; derived at build time from the user's CShapes 2.0 copy (CC BY-NC-SA 4.0,",
+                    "not redistributed); GeoNames (CC BY 4.0); Unicode CLDR; ISO 3166-3 via Debian iso-codes")
+  )
+  saveRDS(provenance, gnrs_provenance_path("history", dir))
+  gnrs_env$history <- NULL
+  if (!quiet) {
+    message("  ", provenance$n_historical, " historical entities, ", provenance$n_names,
+            " names, ", provenance$n_lineage, " lineage links")
+  }
+  invisible(provenance)
+}
+
+#' The history tables, cached for the session
+#' @keywords internal
+#' @noRd
+gnrs_history <- function(dir = gnrs_cache_dir()) {
+  paths <- gnrs_history_path(c("entities", "names", "lineage", "periods"), dir)
+  if (!all(file.exists(paths))) {
+    stop("The history component has not been built. Run GNRS_local_build(\"history\").", call. = FALSE)
+  }
+  key <- paste(paths, file.mtime(paths), collapse = "|")
+  if (identical(gnrs_env$history_key, key) && !is.null(gnrs_env$history)) {
+    return(gnrs_env$history)
+  }
+  rd <- function(p) as.data.frame(nanoparquet::read_parquet(p))
+  h <- list(entities = rd(paths[1]), names = rd(paths[2]), lineage = rd(paths[3]), periods = rd(paths[4]))
+  gnrs_env$history <- h
+  gnrs_env$history_key <- key
+  h
+}
+
+#' The backbone with historical countries added
+#'
+#' Internal.  Historical entities are appended to the country table and their
+#' names (and former names of continuing states) to the country name table, as
+#' alternate names, so the unchanged cascade finds them by exact or fuzzy
+#' alternate name.  They carry no ISO or GADM codes.  The copy has its own match
+#' cache, so indexes built for the current-only backbone are not reused.
+#'
+#' With \code{alternate_names = FALSE} only each entity's own name and its
+#' ISO 3166-3 codes are appended, as \code{gnrs_without_alternate_names()}
+#' keeps only the current divisions' own names: the curated, CShapes and
+#' GeoNames aliases are alternate names in the same sense.
+#' @keywords internal
+#' @noRd
+gnrs_backbone_with_history <- function(bb, dir = gnrs_cache_dir(), alternate_names = TRUE) {
+  h <- gnrs_history(dir)
+  he <- h$entities[h$entities$kind == "historical", , drop = FALSE]
+  co <- bb$country
+  add <- co[rep(NA_integer_, nrow(he)), , drop = FALSE]
+  add$country_id <- he$entity_id
+  add$country <- he$short_name
+  if ("is_geoname" %in% names(add)) add$is_geoname <- !is.na(he$geonameid)
+  add$lower <- gnrs_lower(add$country)
+  # Synthetic entities made from CShapes colonies match their standard name exactly only;
+  # per-name fuzzy flags for alternate names come from the shipped names table. On GBIF
+  # names, fuzzy matching of such names drew records away from the right current country
+  # ("N. Rhodesia", correctly Zambia, went to Zimbabwe via "Rhodesia").
+  # synthetic keys are CSH followed by the CShapes code; note Czechoslovakia is CSHH
+  synthetic <- grepl("^CSH[0-9]+$", he$entity_key)
+  co$fuzzy <- TRUE
+  add$fuzzy <- !synthetic
+  country <- rbind(co, add)
+  country <- country[order(country$country_id), , drop = FALSE]
+  rownames(country) <- NULL
+
+  cn <- bb$country_names
+  new_names <- data.frame(
+    level = "country", id = h$names$entity_id, name = h$names$name,
+    name_type = paste("historical:", h$names$source), stringsAsFactors = FALSE
+  )
+  keep <- !is.na(new_names$id)
+  if (!alternate_names) {
+    keep <- keep & h$names$source %in% c("entity name", "ISO 3166-3")
+  }
+  new_names <- new_names[keep, , drop = FALSE]
+  new_names$lower <- gnrs_lower(new_names$name)
+  new_names$original <- TRUE
+  # per-name decision shipped in history_names.csv (data-raw/history_crosswalk.R)
+  new_names$fuzzy <- as.logical(h$names$fuzzy[keep])
+  cn$fuzzy <- TRUE
+  for (col in setdiff(names(cn), names(new_names))) new_names[[col]] <- NA
+  new_names <- new_names[, names(cn), drop = FALSE]
+  country_names <- rbind(cn, new_names)
+  country_names <- country_names[order(country_names$id, country_names$name), , drop = FALSE]
+  rownames(country_names) <- NULL
+
+  bb2 <- bb
+  bb2$country <- country
+  bb2$country_names <- country_names
+  bb2$country_name_rows_by_id <- split(seq_len(nrow(country_names)), country_names$id)
+  bb2$cache <- new.env(parent = emptyenv())
+  bb2$history_ids <- he$entity_id
+  bb2
+}
+
+#' Parse the optional date column: a year, an ISO date, or a Date
+#' @keywords internal
+#' @noRd
+gnrs_parse_record_date <- function(x) {
+  if (is.null(x)) {
+    return(NULL)
+  }
+  if (inherits(x, "Date")) {
+    return(x)
+  }
+  x <- trimws(as.character(x))
+  out <- rep(as.Date(NA), length(x))
+  year <- !is.na(x) & grepl("^[0-9]{3,4}$", x)
+  if (any(year)) out[year] <- as.Date(sprintf("%04d-07-01", as.integer(x[year])))
+  iso <- !is.na(x) & !year & grepl("^[0-9]{4}-[0-9]{2}", x)
+  # guarded: paste0(character(0), "-01") is "-01", not character(0)
+  if (any(iso)) out[iso] <- suppressWarnings(as.Date(substr(paste0(x[iso], "-01"), 1, 10)))
+  out
+}
+
+#' Does a submitted name mark the division as former?
+#'
+#' Internal.  "Former USSR", "Ex-USSR", "EX-YUGOSLAVIA", "Czechoslovakia (former)",
+#' "formerly Zaire", and the German, Spanish and French equivalents ("ehemalige",
+#' "antigua", "ancienne").
+#' @keywords internal
+#' @noRd
+gnrs_is_former_label <- function(x) {
+  x <- gnrs_unaccent(tolower(ifelse(is.na(x), "", x)))
+  grepl("(^|[^a-z])(former|formerly|ex|ehemalig[a-z]*|antigu[ao]s?|ancien(ne)?s?)([^a-z]|$)", x, perl = TRUE)
+}
+
+#' Current successors of a historical entity, following the lineage to the present
+#'
+#' Internal.  The lineage is followed through current countries as well as
+#' former ones: a current country can itself have later successors (Kosovo
+#' seceded from Serbia in 2008, so it descends from Yugoslavia through
+#' Serbia), and every node is visited once.
+#' @keywords internal
+#' @noRd
+gnrs_current_successors <- function(entity_id, h) {
+  cur <- h$entities$entity_id[h$entities$kind == "current"]
+  seen <- entity_id
+  front <- entity_id
+  out <- integer(0)
+  while (length(front)) {
+    nxt <- setdiff(unique(h$lineage$to_id[h$lineage$from_id %in% front]), seen)
+    seen <- c(seen, nxt)
+    out <- c(out, intersect(nxt, cur))
+    front <- nxt
+  }
+  unique(out)
+}
+
+#' Resolve with historical divisions
+#'
+#' Internal.  \code{u} is the distinct-row table GNRS_local passes to
+#' \code{gnrs_resolve()}; \code{m} maps input rows to it; \code{dates} are the
+#' parsed input dates (or NULL).  Returns the per-input-row resolution plus the
+#' history columns.
+#'
+#' \describe{
+#'   \item{history = "all"}{Resolve against current and historical countries
+#'     together.  A current country wins an exact tie (colliding historical names
+#'     from non-curated sources were dropped at build).}
+#'   \item{history = "at_date"}{As "all", but a historical match whose validity
+#'     does not include the record's date (with \code{tolerance_years} either
+#'     side) is replaced by the current-only resolution of that row.  Rows without
+#'     a date keep the "all" answer, flagged.}
+#' }
+#' A state or county submitted under a historical country is resolved within the
+#' entity's current successors (the USSR's successors for "USSR" / "Kamchatka"),
+#' and the successor used is reported; if none contains it, the sub-national
+#' result is "unverifiable".
+#' @keywords internal
+#' @noRd
+gnrs_resolve_history <- function(u, m, dates, bb_current, dir, threshold, history, tolerance_years = 1, alternate_names = TRUE) {
+  h <- gnrs_history(dir)
+  bb_all <- gnrs_backbone_with_history(bb_current, dir, alternate_names = alternate_names)
+
+  old <- gnrs_env$backbone
+  on.exit(gnrs_env$backbone <- old, add = TRUE)
+
+  gnrs_env$backbone <- bb_all
+  r_all <- gnrs_resolve(u, bb_all, threshold = threshold)
+  gnrs_env$backbone <- bb_current
+  r_cur <- gnrs_resolve(u, bb_current, threshold = threshold)
+
+  ent <- h$entities
+  is_hist_id <- function(id) !is.na(id) & id %in% bb_all$history_ids
+
+  # ---- sub-national names under a historical country: resolve within successors
+  r_all$subnational_resolved_in <- NA_character_
+  r_all$subnational_status <- NA_character_
+  hrows <- which(is_hist_id(r_all$country_id))
+  sub_rows <- hrows[!gnrs_blank(u$state_province_verbatim[hrows]) | !gnrs_blank(u$county_parish_verbatim[hrows])]
+  if (length(sub_rows)) {
+    cand <- do.call(rbind, lapply(sub_rows, function(i) {
+      succ <- gnrs_current_successors(r_all$country_id[i], h)
+      if (!length(succ)) return(NULL)
+      data.frame(row = i, successor_id = succ,
+                 country_verbatim = bb_current$country$country[match(succ, bb_current$country$country_id)],
+                 state_province_verbatim = u$state_province_verbatim[i],
+                 county_parish_verbatim = u$county_parish_verbatim[i], stringsAsFactors = FALSE)
+    }))
+    # successors the current backbone lacks are dropped before, not after, the
+    # emptiness test
+    if (!is.null(cand)) cand <- cand[!is.na(cand$country_verbatim), , drop = FALSE]
+    if (!is.null(cand) && nrow(cand)) {
+      rs <- gnrs_resolve(cand[, c("country_verbatim", "state_province_verbatim", "county_parish_verbatim")],
+                         bb_current, threshold = threshold)
+      rs$row <- cand$row
+      rs$successor_id <- cand$successor_id
+      ok <- !is.na(rs$state_province_id)
+      rs <- rs[ok, , drop = FALSE]
+      if (nrow(rs)) {
+        exact <- !grepl("^fuzzy", rs$match_method_state_province)
+        score <- ifelse(is.na(rs$match_score_state_province), 1, rs$match_score_state_province)
+        rs <- rs[order(rs$row, -exact, -score, rs$successor_id), , drop = FALSE]
+        rs <- rs[!duplicated(rs$row), , drop = FALSE]
+        cols <- c("state_province", "state_province_id", "county_parish", "county_parish_id",
+                  "match_method_state_province", "match_method_county_parish",
+                  "match_score_state_province", "match_score_county_parish",
+                  "state_province_iso", "county_parish_iso", "gid_1", "gid_2")
+        cols <- intersect(cols, intersect(names(rs), names(r_all)))
+        r_all[rs$row, cols] <- rs[, cols]
+        r_all$subnational_resolved_in[rs$row] <- ent$entity_key[match(rs$successor_id, ent$entity_id)]
+        r_all$subnational_status[rs$row] <- "resolved in successor"
+        # the match level and status were summarized before the state was filled in
+        sv <- u$state_province_verbatim[rs$row]
+        cv <- u$county_parish_verbatim[rs$row]
+        lvl_sub <- ifelse(gnrs_blank(cv), "state_province", "county_parish")
+        lvl_mat <- ifelse(is.na(r_all$county_parish_id[rs$row]), "state_province", "county_parish")
+        r_all$poldiv_submitted[rs$row] <- lvl_sub
+        r_all$poldiv_matched[rs$row] <- lvl_mat
+        r_all$match_status[rs$row] <- ifelse(lvl_sub == lvl_mat, "full match", "partial match")
+        # ... as were the lowest matched identifier and the overall score, which
+        # combines the historical country's score with the successor's divisions'
+        r_all$geonameid[rs$row] <- ifelse(is.na(rs$county_parish_id), rs$state_province_id, rs$county_parish_id)
+        sc <- r_all$match_score_country[rs$row]
+        ss <- rs$match_score_state_province
+        sk <- rs$match_score_county_parish
+        overall <- ifelse(is.na(sk), (sc + ss) / 2, (sc + ss + sk) / 3)
+        r_all$overall_score[rs$row] <- gnrs_numeric2(overall)
+      }
+    }
+    unres <- sub_rows[is.na(r_all$subnational_status[sub_rows])]
+    r_all$subnational_status[unres] <- "unverifiable"
+  }
+
+  # ---- per input row
+  out <- r_all[m, , drop = FALSE]
+  cur_rows <- r_cur[m, , drop = FALSE]
+  hist_match <- is_hist_id(out$country_id)
+  e <- match(out$country_id, ent$entity_id)
+  out$entity_key <- ent$entity_key[e]
+  out$is_historical <- ifelse(is.na(out$country_id), NA, hist_match)
+  out$entity_valid_from <- ent$valid_from[e]
+  out$entity_valid_to <- ent$valid_to[e]
+  out$successors <- vapply(seq_len(nrow(out)), function(i) {
+    if (!isTRUE(hist_match[i])) return(NA_character_)
+    s <- gnrs_current_successors(out$country_id[i], h)
+    paste(ent$entity_key[match(s, ent$entity_id)], collapse = ";")
+  }, character(1))
+  out$date_check <- NA_character_
+
+  if (history == "at_date") {
+    from <- as.Date(out$entity_valid_from)
+    to <- as.Date(out$entity_valid_to)
+    tol <- 365.25 * tolerance_years
+    has_date <- !is.null(dates) & !is.na(dates)
+    if (is.null(dates)) has_date <- rep(FALSE, nrow(out))
+    inside <- (is.na(from) | dates >= from - tol) & (is.na(to) | dates <= to + tol)
+    # A name that marks the division as former ("Former USSR", "Ex-Yugoslavia",
+    # "Czechoslovakia (former)") is correct for any date after the division ended: it
+    # places the record in the former territory (BM, 2026-09-17). Dates before the
+    # division existed are still rejected.
+    former_label <- gnrs_is_former_label(out$country_verbatim)
+    after_end <- has_date & !is.na(to) & dates > to + tol
+    exempt <- hist_match & !inside & former_label & after_end
+    # A state or county resolved within a successor is kept, and flagged, even when the
+    # record's date falls outside the former country's existence ("USSR" + "Kamchatka"
+    # dated 2005): the place is identified, only the country label is out of date
+    # (BM, 2026-09-17).
+    kept_sub <- hist_match & has_date & !inside & !exempt & (out$subnational_status %in% "resolved in successor")
+    replace <- hist_match & has_date & !inside & !exempt & !kept_sub
+    out$date_check[hist_match & has_date & inside] <- "historical entity valid at record date"
+    out$date_check[exempt] <- "record dated after the entity ended, but named as former; historical match kept"
+    out$date_check[kept_sub] <- paste("historical match outside its validity at the record date;",
+                                      "kept because the state or county resolves in a successor")
+    out$date_check[hist_match & !has_date] <- "no record date; historical match kept"
+    if (any(replace)) {
+      keep_cols <- names(cur_rows)
+      out[replace, keep_cols] <- cur_rows[replace, keep_cols]
+      out$entity_key[replace] <- ent$entity_key[match(out$country_id[replace], ent$entity_id)]
+      out$is_historical[replace] <- FALSE
+      out$entity_valid_from[replace] <- NA
+      out$entity_valid_to[replace] <- NA
+      out$successors[replace] <- NA
+      out$subnational_resolved_in[replace] <- NA
+      out$subnational_status[replace] <- NA
+      out$date_check[replace] <- "historical match outside its validity at the record date; current-only resolution used"
+    }
+  }
+  out
+}
diff --git a/R/local_reference.R b/R/local_reference.R
index 4b10d97..910c1ad 100644
--- a/R/local_reference.R
+++ b/R/local_reference.R
@@ -225,6 +225,9 @@ gnrs_backbone <- function(dir = gnrs_cache_dir(), quiet = FALSE) {
     sep = sep
   )
 
+  # the alternative and superseded divisions, so a resolution step can reach them
+  # without the cache directory being threaded through every call
+  backbone$altdiv <- gnrs_altdiv(dir)
   gnrs_env$key <- key
   gnrs_env$backbone <- backbone
   backbone
@@ -262,10 +265,16 @@ gnrs_scope <- function(bb, what, parent = NA, index = FALSE) {
   co <- bb$country
 
   scope <- switch(what,
-    # Every country, by its standard name
-    country_std = pick(co, seq_len(nrow(co)), "country_id", "country"),
-    # Every country's GeoNames alternate names
-    country_alt = pick(bb$country_names, which(bb$country_names$original), "id", "name"),
+    # Every country, by its standard name.  Rows flagged fuzzy = FALSE (added by the
+    # history component) take part in exact matching only.
+    country_std = pick(co, if (is.null(co$fuzzy)) seq_len(nrow(co)) else which(co$fuzzy %in% TRUE),
+                       "country_id", "country"),
+    # Every country's GeoNames alternate names (and, with the history component,
+    # historical names flagged for fuzzy matching)
+    country_alt = pick(bb$country_names,
+                       which(bb$country_names$original &
+                         (if (is.null(bb$country_names$fuzzy)) TRUE else bb$country_names$fuzzy %in% TRUE)),
+                       "id", "name"),
     # Countries that are subdivisions of the given country, by standard name
     sac_std = pick(co, which(!is.na(co$alt_country_id) & co$alt_country_id == parent), "country_id", "country"),
     # Their alternate names, of every type
diff --git a/R/local_resolve.R b/R/local_resolve.R
index 9d07608..00947a6 100644
--- a/R/local_resolve.R
+++ b/R/local_resolve.R
@@ -48,6 +48,13 @@ gnrs_resolve <- function(u, bb, threshold = 0.5) {
   u$match_score_country <- na_num
   u$match_score_state_province <- na_num
   u$match_score_county_parish <- na_num
+  # a declared division that belongs to another division system (Swedish landskap,
+  # Watsonian vice-counties, Norwegian counties after the 2018 and 2020 reforms):
+  # recognised as itself rather than forced onto the nearest-looking GADM unit
+  u$alt_division <- na_chr
+  u$alt_division_system <- na_chr
+  u$alt_division_level <- na_chr
+  u$alt_division_extent_known <- rep(NA, nrow(u))
 
   if (n == 0) {
     return(gnrs_summarize(u, bb))
@@ -60,10 +67,14 @@ gnrs_resolve <- function(u, bb, threshold = 0.5) {
   u <- gnrs_step_countryasstate_exact(u, ctx)
   u <- gnrs_step_countryasstate_fuzzy(u, ctx)
   u <- gnrs_step_state_exact(u, ctx)
+  u <- gnrs_step_altdiv(u, ctx, "state")
+  u <- gnrs_step_state_altname(u, ctx)
   u <- gnrs_step_state_fuzzy(u, ctx)
   u <- gnrs_step_stateascountry_exact(u, ctx)
   u <- gnrs_step_stateascountry_fuzzy(u, ctx)
   u <- gnrs_step_county_exact(u, ctx)
+  u <- gnrs_step_altdiv(u, ctx, "county")
+  u <- gnrs_step_county_altname(u, ctx)
   u <- gnrs_step_county_fuzzy(u, ctx)
   u <- gnrs_step_stateascounty_exact(u, ctx)
   u <- gnrs_step_stateascounty_fuzzy(u, ctx)
@@ -366,6 +377,21 @@ gnrs_step_state_exact <- function(u, ctx) {
     u <- gnrs_set_state(u, hit$rows, hit$ids, t[[3]])
   }
 
+  u
+}
+
+#' The exact match on a state's GeoNames alternate names
+#'
+#' Internal.  Split from \code{gnrs_step_state_exact()} so that
+#' \code{gnrs_step_altdiv()} can run between the two: a name that IS a GADM unit's
+#' own name wins, a name that is only an alternate of one does not.
+#' @keywords internal
+#' @noRd
+gnrs_step_state_altname <- function(u, ctx) {
+  st <- ctx$bb$state
+  sn <- ctx$bb$state_names
+  sv <- u$state_province_verbatim
+  cid <- u$country_id
   rows <- which(!is.na(cid) & is.na(u$state_province_id) &
     is.na(u$match_method_state_province) & !gnrs_blank(sv))
   hit <- gnrs_exact(rows, gnrs_key(cid[rows], sv[rows]), sn$key_original, sn$id)
@@ -547,11 +573,90 @@ gnrs_step_county_exact <- function(u, ctx) {
     u <- gnrs_set_county(u, hit$rows, hit$ids, t[[3]])
   }
 
-  rows <- which(!is.na(u$country_id) & !is.na(sid) & is.na(u$county_parish_id) & !gnrs_blank(cpv))
+  u
+}
+
+#' The exact match on a county's GeoNames alternate names
+#' @keywords internal
+#' @noRd
+gnrs_step_county_altname <- function(u, ctx) {
+  cn <- ctx$bb$county_names
+  cpv <- u$county_parish_verbatim
+  sid <- u$state_province_id
+  rows <- which(!is.na(u$country_id) & !is.na(sid) & is.na(u$county_parish_id) &
+    is.na(u$match_method_county_parish) & !gnrs_blank(cpv))
   hit <- gnrs_exact(rows, gnrs_key(sid[rows], cpv[rows]), cn$key_original, cn$id)
   gnrs_set_county(u, hit$rows, hit$ids, "exact alternate name")
 }
 
+#' Recognise a declared division that belongs to another division system
+#'
+#' Internal.  Runs between the exact matches on a GADM unit's OWN names and codes
+#' and the match on its GeoNames alternate names, which is the precedence the data
+#' calls for: Skane is both a landskap and a lan and stays the lan, while Uppland is
+#' a landskap and stops being matched to Uppsala lan, a division it is not in.
+#'
+#' Nothing is written to \code{state_province_id} or \code{county_parish_id},
+#' because these are not GADM divisions. The match method records what was
+#' recognised, which also stops the later steps, and the \code{alt_division_*}
+#' columns carry it to the caller. Where both levels are recognised the finer one
+#' is reported.
+#' @keywords internal
+#' @noRd
+gnrs_step_altdiv <- function(u, ctx, level = c("state", "county")) {
+  level <- match.arg(level)
+  a <- ctx$bb$altdiv
+  if (is.null(a)) return(u)
+  iso <- ctx$bb$country$iso[match(u$country_id, ctx$bb$country$country_id)]
+  if (level == "state") {
+    v <- u$state_province_verbatim
+    rows <- which(!is.na(u$country_id) & is.na(u$state_province_id) &
+      is.na(u$match_method_state_province) & !gnrs_blank(v))
+  } else {
+    v <- u$county_parish_verbatim
+    # a county is only looked up once its state is known, EXCEPT here: the declared
+    # state may itself be an alternative division, in which case there is no state id
+    rows <- which(!is.na(u$country_id) & is.na(u$county_parish_id) &
+      is.na(u$match_method_county_parish) & !gnrs_blank(v))
+  }
+  if (!length(rows)) return(u)
+  # no dates here: the period of a superseded division is checked where record dates
+  # live, in the geovalidity test, not in name resolution
+  m <- gnrs_altdiv_match(iso[rows], v[rows], altdiv = a)
+  ok <- which(!is.na(m$entity_key))
+  if (!length(ok)) return(u)
+  r <- rows[ok]
+  method <- paste0("alternative division (", m$system[ok], ")")
+
+  # An ALIAS is the same GADM unit under another name - "Norrbottens lan" IS
+  # Norrbotten - so it resolves like any other match and stays in the ordinary output.
+  # Only units that are genuinely not GADM divisions are left unresolved and reported
+  # through alt_division.
+  for (j in which(m$kind[ok] == "alias")) {
+    gid <- a$extent$gid[a$extent$entity_key == m$entity_key[ok][j]]
+    if (length(gid) != 1L) next
+    if (level == "state") {
+      id <- ctx$bb$state$state_province_id[match(gid, ctx$bb$state$gid_1)]
+      if (!is.na(id)) u <- gnrs_set_state(u, r[j], id, method[j])
+    } else {
+      id <- ctx$bb$county$county_parish_id[match(gid, ctx$bb$county$gid_2)]
+      if (!is.na(id)) u <- gnrs_set_county(u, r[j], id, method[j])
+    }
+  }
+  if (level == "state") {
+    u$match_method_state_province[r] <- ifelse(is.na(u$match_method_state_province[r]),
+                                               method, u$match_method_state_province[r])
+  } else {
+    u$match_method_county_parish[r] <- ifelse(is.na(u$match_method_county_parish[r]),
+                                              method, u$match_method_county_parish[r])
+  }
+  u$alt_division[r] <- m$entity_key[ok]
+  u$alt_division_system[r] <- m$system[ok]
+  u$alt_division_level[r] <- level
+  u$alt_division_extent_known[r] <- m$extent_known[ok]
+  u
+}
+
 gnrs_step_county_fuzzy <- function(u, ctx) {
   cpv <- u$county_parish_verbatim
   sid <- u$state_province_id
diff --git a/data-raw/altdiv.R b/data-raw/altdiv.R
new file mode 100644
index 0000000..13179b4
--- /dev/null
+++ b/data-raw/altdiv.R
@@ -0,0 +1,155 @@
+# ---------------------------------------------------------------------------
+# data-raw/altdiv.R
+#
+# Generates the curated tables of ALTERNATIVE and SUPERSEDED sub-national
+# divisions, which ship with the package in inst/extdata/:
+#
+#   altdiv_units.csv   one row per unit: which system it belongs to, its country,
+#                      and, for superseded units, the dates it existed
+#   altdiv_names.csv   the names records use for it; match = "exact" or "regex"
+#   altdiv_extent.csv  the GADM units a unit covers, where that is known
+#
+# Why this exists. GNRS resolves a declared state or county against GADM. Large
+# parts of the record stream declare divisions that are not GADM divisions at all:
+#
+#   Sweden   landskap (provinces) and lappmarker are a parallel traditional system;
+#            a landskap spans several lan and vice versa. 53.6% of Swedish records
+#            with a declared state use one (Smaland 3.7M records, Uppland 3.0M,
+#            Vastergotland 2.8M).
+#   Britain  the declared county is a Watsonian vice-county, the botanical
+#            recording unit, frozen at 1852 boundaries: 99.7% of British records
+#            with a declared county, written "VC57 Derbyshire".
+#   Norway   the declared county is post-reform (Viken, Innlandet, Vestland,
+#            Trondelag); GADM 4.1 still carries the pre-2018 counties.
+#
+# Without this, GNRS matches such a name to the nearest-looking GADM unit - a
+# landskap onto a lan - and the coordinate then falls in a different unit, so the
+# record looks geo-invalid when it is correctly georeferenced and correctly
+# labelled in its own system. Measured on the garden pipeline, that mislabelled
+# 19.8M records as invalid, 70% of them from these three countries.
+#
+# A unit with a known EXTENT can be validated properly: the coordinate must fall in
+# one of the GADM units the declared unit covers. A unit with no extent yet is
+# UNVERIFIABLE - recognised, never called invalid.
+#
+# Extents shipped here are only those that are exactly determined. Swedish
+# landskap and lappmarker and the British vice-counties need their boundaries,
+# which is a separate sourcing and licensing job (see the GNRS issue).
+# ---------------------------------------------------------------------------
+suppressMessages({library(data.table); library(nanoparquet)})
+
+# Run from the package root.  The GADM unit index (RGVS's gadmindex-units
+# parquet) is read from wherever GNRS_GADM_INDEX points.
+if (!file.exists("DESCRIPTION")) stop("Run this script from the package root.")
+OUT <- file.path("inst", "extdata")
+GADM <- Sys.getenv("GNRS_GADM_INDEX", unset = NA)
+if (is.na(GADM)) stop("Set GNRS_GADM_INDEX to the path of the GADM unit index parquet.")
+dir.create(OUT, recursive = TRUE, showWarnings = FALSE)
+D <- function(x) as.Date(x)
+units <- list(); names_ <- list(); extent <- list()
+
+add <- function(system, entity_key, country_iso, name, kind, valid_from = NA, valid_to = NA,
+                note = NA_character_, alt = character(0), gids = character(0), level = NA_integer_,
+                match = "exact", register_name = TRUE) {
+  units[[length(units) + 1]] <<- data.table(system, entity_key, country_iso, name, kind,
+                                            valid_from = D(valid_from), valid_to = D(valid_to), note)
+  # the unit's own name is always an exact lookup; only the alternates carry `match`,
+  # so a regex system ("^VC ?[0-9]+") does not register its label as a pattern. A system
+  # whose label nobody writes in a record (the vice-counties) supplies alternates only.
+  if (match == "exact" && register_name) {
+    names_[[length(names_) + 1]] <<- data.table(entity_key, name = name, match = "exact")
+  }
+  if (length(alt)) {
+    names_[[length(names_) + 1]] <<- data.table(entity_key, name = alt, match = match)
+  }
+  if (length(gids)) {
+    extent[[length(extent) + 1]] <<- data.table(entity_key, level = as.integer(level), gid = gids)
+  }
+}
+
+# ---- Norway: counties superseded by the 2018 and 2020 reforms -------------------
+# GADM 4.1 carries the 19 pre-2018 counties. The 2020 reform merged them into 11;
+# on 2024-01-01 three of those were dissolved and their predecessors re-established,
+# so those names are period-specific. Oslo, Nordland, Rogaland and More og Romsdal
+# were unchanged and need no entry: they match GADM directly.
+n <- function(key, name, from, to, gids, note) {
+  add("no-fylke", key, "NO", name, "superseded", from, to, note, gids = gids, level = 1L)
+}
+n("NO-TRONDELAG", "Tr\u00f8ndelag", "2018-01-01", NA,
+  c("NOR.9_1", "NOR.15_1"), "2018 merger of Nord-Tr\u00f8ndelag and S\u00f8r-Tr\u00f8ndelag")
+n("NO-VIKEN", "Viken", "2020-01-01", "2023-12-31",
+  c("NOR.1_1", "NOR.4_1", "NOR.2_1"), "Akershus, Buskerud and \u00d8stfold; dissolved 2024-01-01")
+n("NO-INNLANDET", "Innlandet", "2020-01-01", NA,
+  c("NOR.6_1", "NOR.11_1"), "Hedmark and Oppland")
+n("NO-VESTLAND", "Vestland", "2020-01-01", NA,
+  c("NOR.7_1", "NOR.14_1"), "Hordaland and Sogn og Fjordane")
+n("NO-VESTFOLD-TELEMARK", "Vestfold og Telemark", "2020-01-01", "2023-12-31",
+  c("NOR.19_1", "NOR.16_1"), "Vestfold and Telemark; dissolved 2024-01-01")
+n("NO-TROMS-FINNMARK", "Troms og Finnmark", "2020-01-01", "2023-12-31",
+  c("NOR.17_1", "NOR.5_1"), "Troms and Finnmark; dissolved 2024-01-01")
+n("NO-AGDER", "Agder", "2020-01-01", NA,
+  c("NOR.3_1", "NOR.18_1"), "Aust-Agder and Vest-Agder")
+
+# ---- Sweden: the lan under the names records actually use -----------------------
+# GADM stores the bare name ("Norrbotten"); records write "Norrbottens lan" or
+# "Norrbotten lan". These are the SAME unit, so they are aliases with a one-unit
+# extent: recognising them ADDS validation rather than suppressing it. Both the
+# genitive and the plain form are generated; whichever does not occur simply never
+# matches.
+#
+# The BARE name is registered too, because the GNRS reference names these units
+# inconsistently - "Norrbotten" but "Vastmanlands lan", "Vestfold fylke" - so a record
+# saying "Skane" does not match the reference's "Skane lan" exactly and would
+# otherwise fall through to the landskap of the same name and lose a unit it could
+# have been checked against. Where a name matches both, the matcher prefers the entry
+# that has an extent, which is this one.
+gadm <- as.data.table(nanoparquet::read_parquet(GADM))
+lan <- unique(gadm[gid_0 == "SWE", .(gid_1, name_1)])
+for (i in seq_len(nrow(lan))) {
+  add("se-lan-alias", paste0("SE-LAN-", lan$gid_1[i]), "SE", lan$name_1[i], "alias",
+      note = "the same GADM unit under the name records use",
+      alt = paste0(lan$name_1[i], c(" l\u00e4n", "s l\u00e4n")),
+      gids = lan$gid_1[i], level = 1L)
+}
+
+# ---- Sweden: landskap (provinces), a parallel traditional system -----------------
+# 25 units. Where a landskap shares its name with a lan (Skane, Gotland, Halland and
+# others) the exact GADM match wins and this entry never fires; the ones that matter
+# are those with no lan of the same name (Smaland, Uppland, Vastergotland ...).
+landskap <- c("Blekinge", "Bohusl\u00e4n", "Dalarna", "Dalsland", "Gotland", "G\u00e4strikland",
+              "Halland", "H\u00e4lsingland", "H\u00e4rjedalen", "J\u00e4mtland", "Lappland",
+              "Medelpad", "Norrbotten", "N\u00e4rke", "Sk\u00e5ne", "Sm\u00e5land",
+              "S\u00f6dermanland", "Uppland", "V\u00e4rmland", "V\u00e4sterbotten",
+              "V\u00e4sterg\u00f6tland", "V\u00e4stmanland", "\u00c5ngermanland", "\u00d6land",
+              "\u00d6sterg\u00f6tland")
+for (x in landskap) {
+  add("se-landskap", paste0("SE-LS-", gsub("[^A-Za-z]", "", iconv(x, "UTF-8", "ASCII//TRANSLIT"))),
+      "SE", x, "parallel", note = "landskap (province); extent not yet sourced")
+}
+
+# ---- Sweden: lappmarker ----------------------------------------------------------
+for (x in c("Lule", "Lycksele", "Pite", "Torne", "\u00c5sele")) {
+  add("se-lappmark", paste0("SE-LP-", gsub("[^A-Za-z]", "", iconv(x, "UTF-8", "ASCII//TRANSLIT"))),
+      "SE", paste(x, "lappmark"), "parallel", note = "lappmark; extent not yet sourced")
+}
+
+# ---- Britain and Ireland: Watsonian vice-counties ---------------------------------
+# 112 vice-counties in Great Britain and 40 in Ireland, written "VC57 Derbyshire".
+# One entry recognises the whole system by the way records write it; the individual
+# units are only needed once their boundaries are sourced, which is what would give
+# them an extent.
+for (cc in c("GB", "IE")) {
+  add("gb-vice-county", paste0(cc, "-VC"), cc, "Watsonian vice-county", "parallel",
+      note = "botanical recording unit, boundaries frozen at 1852; extent not yet sourced",
+      alt = "^VC ?[0-9]+", match = "regex")
+}
+
+u <- rbindlist(units); nm <- unique(rbindlist(names_), by = c("entity_key", "name"))
+ex <- if (length(extent)) rbindlist(extent) else data.table(entity_key = character(0), level = integer(0), gid = character(0))
+stopifnot(!anyDuplicated(u$entity_key), all(ex$entity_key %in% u$entity_key), all(nm$entity_key %in% u$entity_key))
+fwrite(u, file.path(OUT, "altdiv_units.csv"))
+fwrite(nm, file.path(OUT, "altdiv_names.csv"))
+fwrite(ex, file.path(OUT, "altdiv_extent.csv"))
+cat(sprintf("units %d (%s) | names %d | extents %d over %d units\n", nrow(u),
+            paste(sprintf("%s %d", names(table(u$system)), table(u$system)), collapse = ", "),
+            nrow(nm), nrow(ex), uniqueN(ex$entity_key)))
diff --git a/data-raw/history_crosswalk.R b/data-raw/history_crosswalk.R
new file mode 100644
index 0000000..23e18bc
--- /dev/null
+++ b/data-raw/history_crosswalk.R
@@ -0,0 +1,255 @@
+# ---------------------------------------------------------------------------
+# data-raw/history_crosswalk.R
+#
+# Generates the CURATED inputs of the time-versioned division reference
+# (dev_notes/04). They ship with the package in inst/extdata/:
+#
+#   history_current_entities.csv  snapshot of the service's current countries
+#   history_curated_entities.csv  historical entities keyed by ISO 3166-3 alpha-4
+#                                 or a synthetic key, with their dates
+#   history_curated_periods.csv   curated assignments of CShapes state codes to
+#                                 entities over periods (gwcode 365 is the Russian
+#                                 Empire, the USSR and the Russian Federation)
+#   history_curated_lineage.csv   curated predecessor -> successor links, CLDR
+#                                 successor lists resolved
+#   history_curated_names.csv     curated names and former names of entities
+#   history_geonames_names.csv    GeoNames names of the historical entities
+#   history_codes.csv             former country codes and the entity each denotes
+#
+# NOTHING DERIVED FROM CShapes SHIPS (BM, 2026-09-22). CShapes 2.0 is CC BY-NC-SA
+# 4.0 and this package is MIT, so the CShapes-derived parts - periods for every
+# uncurated state code, the synthetic CSH<gwcode> entities, their names, the
+# coverage check and the geometry-derived lineage - are computed at build time
+# from the user's own CShapes copy by gnrs_history_assemble() (R/local_history_assemble.R),
+# after GNRS_local_build("cshapes"). This script holds only the curation, which is
+# original work, and extracts from redistributable sources.
+#
+# Modelling rule: a new ENTITY only where the political unit changed (dissolution,
+# unification, partition, absorption, a colony that is not today's country). A pure
+# rename of a continuing state (Burma -> Myanmar, Zaire -> DR Congo, Dahomey -> Benin,
+# Byelorussian SSR -> Belarus, Russian Empire / RSFSR -> Russian Federation outside
+# the USSR period) stays ONE entity; its former names and codes go in the names and
+# codes tables with their periods.
+#
+# Sources (read from gvs_ms/data/history_sources/, downloaded 2026-09-16), all
+# redistributable in this form:
+#   GNRS country table (the service's own identifiers; cached API snapshot; names
+#     and GeoNames ids, CC BY 4.0)
+#   Unicode CLDR supplementalMetadata.xml territoryAlias (Unicode License v3)
+#   Debian iso-codes iso_3166-3.json (LGPL-2.1+)
+#   GeoNames allCountries, PCLH historical political entities (CC BY 4.0)
+# Every curated decision is written as data below, with a note.
+# ---------------------------------------------------------------------------
+
+suppressMessages({library(data.table); library(nanoparquet); library(jsonlite); library(arrow)})
+
+# Run from the package root.  The source downloads (CLDR, GeoNames, ...) live
+# wherever GNRS_HISTORY_SOURCES points; the service's country table is read
+# from the package's own cache, built with GNRS_local_build().
+SRC <- Sys.getenv("GNRS_HISTORY_SOURCES", unset = NA)
+if (is.na(SRC)) stop("Set GNRS_HISTORY_SOURCES to the directory holding the source downloads.")
+GNRS_CACHE <- Sys.getenv("GNRS_CACHE_DIR", unset = tools::R_user_dir("GNRS", "cache"))
+OUT <- file.path("inst", "extdata")
+if (!file.exists("DESCRIPTION")) stop("Run this script from the package root.")
+dir.create(OUT, recursive = TRUE, showWarnings = FALSE)
+D <- function(x) as.Date(x)
+
+# ---- current entities: the service's country table --------------------------
+ct <- as.data.table(read_parquet(file.path(GNRS_CACHE, "gnrs-api-country.gz.parquet")))
+cur <- ct[!is.na(iso) & nzchar(iso), .(entity_key = iso, name = country, geonameid = as.character(country_id),
+                                        iso3166_1 = iso, iso3166_3 = NA_character_,
+                                        valid_from = as.Date(NA), valid_to = as.Date(NA), kind = "current",
+                                        note = NA_character_)]
+cur <- unique(cur, by = "entity_key")
+# shipped as a snapshot, as the entities table always carried it: which uncurated state
+# codes map to a current country depends on this list, so it is fixed with the curation
+fwrite(cur, file.path(OUT, "history_current_entities.csv"))
+
+# ---- historical entities (curated) -----------------------------------------
+# valid_from/valid_to: dates of the political unit, not of any one border.
+hist <- rbindlist(list(
+  list("SUHH", "Union of Soviet Socialist Republics", "8354411", NA, "SUHH", D("1922-12-30"), D("1991-12-25"), "historical", "Treaty on the Creation of the USSR to dissolution"),
+  list("CSHH", "Czechoslovakia", "8505031", NA, "CSHH", D("1918-10-28"), D("1992-12-31"), "historical", "including the Czechoslovak Socialist Republic"),
+  list("DDDE", "German Democratic Republic", "8354410", NA, "DDDE", D("1949-10-07"), D("1990-10-02"), "historical", "absorbed by the Federal Republic of Germany"),
+  list("YUCS", "Yugoslavia (Kingdom of Serbs, Croats and Slovenes; Kingdom of Yugoslavia; SFR Yugoslavia)", NA, NA, "YUCS", D("1918-12-01"), D("1992-04-26"), "historical", "no GeoNames PCLH; ISO YUCS also covered FR Yugoslavia, modelled separately as CSXX"),
+  list("CSXX", "Serbia and Montenegro (Federal Republic of Yugoslavia to 2003)", "8505033", NA, "CSXX", D("1992-04-27"), D("2006-06-03"), "historical", "GeoNames also has FR Yugoslavia as 7500737; one state renamed in 2003"),
+  list("YDYE", "People's Democratic Republic of Yemen", "8505034", NA, "YDYE", D("1967-11-30"), D("1990-05-21"), "historical", "merged with the Yemen Arab Republic"),
+  list("VNRV", "Republic of Vietnam", "11608491", NA, NA, D("1955-10-26"), D("1975-04-30"), "historical", "synthetic key; absorbed into Vietnam"),
+  list("ANHH", "Netherlands Antilles", "8505032", NA, "ANHH", D("1954-12-15"), D("2010-10-09"), "historical", "Aruba separated 1986"),
+  list("RUBI", "Ruanda-Urundi", "11612757", NA, NA, D("1922-07-20"), D("1962-06-30"), "historical", "synthetic key; Belgian mandate"),
+  list("GEHH", "Gilbert and Ellice Islands", NA, NA, "GEHH", D("1892-05-27"), D("1975-12-31"), "historical", "split into Kiribati and Tuvalu"),
+  list("PCHH", "Trust Territory of the Pacific Islands", NA, NA, "PCHH", D("1947-07-18"), D("1994-10-01"), "historical", "divided into FM, MH, MP and PW"),
+  list("SKIN", "Sikkim", NA, NA, "SKIN", D("1642-01-01"), D("1975-05-16"), "historical", "absorbed by India"),
+  list("PZPA", "Panama Canal Zone", NA, NA, "PZPA", D("1903-11-18"), D("1979-09-30"), "historical", "returned to Panama"),
+  list("NTHH", "Saudi Arabian-Iraqi Neutral Zone", NA, NA, "NTHH", D("1922-12-02"), D("1991-12-26"), "historical", "divided between SA and IQ"),
+  list("CTKI", "Canton and Enderbury Islands", NA, NA, "CTKI", D("1939-04-06"), D("1979-07-12"), "historical", "to Kiribati"),
+  list("FQHH", "French Southern and Antarctic Territories (former code)", NA, NA, "FQHH", NA, D("1979-12-31"), "historical", "now AQ and TF"),
+  list("CSH665", "Mandatory Palestine", NA, NA, NA, D("1920-04-26"), D("1948-05-14"), "historical", "synthetic key from CShapes 665"),
+  list("CSH3", "Territory of Alaska", NA, NA, NA, D("1867-10-18"), D("1959-01-02"), "historical", "US territory; a US state since 1959"),
+  list("CSH4", "Territory of Hawaii", NA, NA, NA, D("1898-07-07"), D("1959-08-20"), "historical", "US territory; a US state since 1959"),
+  list("CSH21", "Dominion of Newfoundland", NA, NA, NA, D("1907-09-26"), D("1949-03-31"), "historical", "joined Canada"),
+  list("CSH730", "Korea (before partition)", NA, NA, NA, NA, D("1945-08-14"), "historical", "Korean Empire / Japanese Korea; successors KP and KR")
+), use.names = FALSE)
+setnames(hist, names(cur))
+
+
+# ---- CShapes code -> entity over periods ---------------------------------------
+# curated splits and assignments; everything else follows countrycode when it gives a
+# current country, else a synthetic entity CSH<gwcode>
+curated_periods <- rbindlist(list(
+  list(365L, D("1886-01-01"), D("1922-12-29"), "RU", "Russian Empire and Soviet Russia: same continuing state as the Russian Federation (rename rule)"),
+  list(365L, D("1922-12-30"), D("1991-12-25"), "SUHH", "USSR"),
+  list(365L, D("1991-12-26"), D("2019-12-31"), "RU", "Russian Federation"),
+  list(345L, D("1918-12-01"), D("1992-04-26"), "YUCS", "Yugoslavia to the break-up"),
+  list(345L, D("1992-04-27"), D("2006-06-02"), "CSXX", "FR Yugoslavia / Serbia and Montenegro"),
+  list(265L, D("1945-05-08"), D("1990-10-02"), "DDDE", "CShapes starts the unit at the Soviet occupation zone (1945); the GDR was founded 1949-10-07"),
+  list(315L, D("1918-11-11"), D("1992-12-31"), "CSHH", "Czechoslovakia"),
+  list(680L, D("1967-11-30"), D("1990-05-21"), "YDYE", "South Yemen"),
+  list(678L, D("1918-10-30"), D("2019-12-31"), "YE", "Yemen Arab Republic continues as Yemen after unification (ISO YE retained)"),
+  list(816L, D("1954-05-01"), D("2019-12-31"), "VN", "Democratic Republic of Vietnam continues as Vietnam (rename rule)"),
+  list(817L, D("1954-05-01"), D("1975-04-30"), "VNRV", "Republic of Vietnam"),
+  list(515L, D("1920-06-28"), D("1962-06-30"), "RUBI", "Ruanda-Urundi"),
+  list(255L, D("1886-01-01"), D("1945-05-07"), "DE", "German Empire / Reich: same continuing state as Germany (rename rule)"),
+  list(6L, D("1886-01-01"), D("2019-12-31"), "PR", "territory still exists"),
+  list(65L, D("1886-01-01"), D("2019-12-31"), "GP", "territory still exists"),
+  list(66L, D("1886-01-01"), D("2019-12-31"), "MQ", "territory still exists"),
+  list(120L, D("1886-01-01"), D("2019-12-31"), "GF", "territory still exists"),
+  list(585L, D("1886-01-01"), D("2019-12-31"), "RE", "territory still exists"),
+  list(930L, D("1886-01-01"), D("2019-12-31"), "NC", "territory still exists"),
+  list(960L, D("1903-05-19"), D("2019-12-31"), "PF", "territory still exists"),
+  list(347L, D("2008-02-20"), D("2019-12-31"), "XK", "Kosovo"),
+  list(609L, D("1958-10-10"), D("1975-11-13"), "EH", "Spanish Sahara is today's Western Sahara territory"),
+  list(6511L, D("1948-05-14"), D("1967-06-09"), "PS", "Gaza under Egyptian administration; territory of today's PS"),
+  list(6631L, D("1948-05-14"), D("1967-06-09"), "PS", "West Bank under Jordanian administration; territory of today's PS"),
+  list(665L, D("1920-04-26"), D("1948-05-13"), "CSH665", "Mandatory Palestine"),
+  list(3L, D("1886-01-01"), D("1959-01-02"), "CSH3", "Territory of Alaska"),
+  list(4L, D("1898-07-06"), D("1959-08-20"), "CSH4", "Territory of Hawaii"),
+  list(21L, D("1886-01-01"), D("1948-07-21"), "CSH21", "Newfoundland"),
+  list(730L, D("1886-01-01"), D("1945-08-14"), "CSH730", "Korea before partition")
+), use.names = FALSE)
+setnames(curated_periods, c("gwcode", "from", "to", "entity_key", "note"))
+curated_periods[, basis := "curated"]
+
+fwrite(curated_periods, file.path(OUT, "history_curated_periods.csv"))
+fwrite(hist, file.path(OUT, "history_curated_entities.csv"))
+
+# ---- lineage ------------------------------------------------------------------
+xml <- readLines(file.path(SRC, "cldr_supplementalMetadata.xml"), encoding = "UTF-8", warn = FALSE)
+ta <- regmatches(xml, regexec('<territoryAlias type="([^"]+)" replacement="([^"]+)" reason="([^"]+)"', xml))
+ta <- rbindlist(lapply(ta[lengths(ta) == 4], function(m) list(code = m[2], replacement = m[3], reason = m[4])))
+cldr_succ <- function(cd) strsplit(ta[code == cd, replacement], " ")[[1]]
+lin <- rbindlist(list(
+  data.table(from_entity = "SUHH", to_entity = cldr_succ("SU"), relation = "dissolution", date = D("1991-12-26"), source = "CLDR territoryAlias SU"),
+  data.table(from_entity = "CSHH", to_entity = cldr_succ("200"), relation = "dissolution", date = D("1993-01-01"), source = "CLDR territoryAlias 200"),
+  data.table(from_entity = "DDDE", to_entity = cldr_succ("DD"), relation = "absorbed", date = D("1990-10-03"), source = "CLDR territoryAlias DD"),
+  data.table(from_entity = "YDYE", to_entity = cldr_succ("YD"), relation = "merged", date = D("1990-05-22"), source = "CLDR territoryAlias YD"),
+  data.table(from_entity = "YUCS", to_entity = c("SI", "HR", "MK", "BA", "CSXX"), relation = "dissolution", date = D("1992-04-27"),
+             source = "CLDR territoryAlias 890 (RS ME replaced by CSXX, their direct predecessor)"),
+  data.table(from_entity = "CSXX", to_entity = cldr_succ("CS"), relation = "dissolution", date = D("2006-06-03"), source = "CLDR territoryAlias CS"),
+  data.table(from_entity = "RS", to_entity = "XK", relation = "secession", date = D("2008-02-17"), source = "curated"),
+  data.table(from_entity = "ANHH", to_entity = cldr_succ("AN"), relation = "dissolution", date = D("2010-10-10"), source = "CLDR territoryAlias AN"),
+  data.table(from_entity = "ANHH", to_entity = "AW", relation = "secession", date = D("1986-01-01"), source = "curated (ISO 3166-3 comment)"),
+  data.table(from_entity = "VNRV", to_entity = "VN", relation = "absorbed", date = D("1976-07-02"), source = "curated"),
+  data.table(from_entity = "RUBI", to_entity = c("RW", "BI"), relation = "dissolution", date = D("1962-07-01"), source = "curated"),
+  data.table(from_entity = "GEHH", to_entity = c("KI", "TV"), relation = "dissolution", date = D("1976-01-01"), source = "ISO 3166-3 comment"),
+  data.table(from_entity = "PCHH", to_entity = c("FM", "MH", "MP", "PW"), relation = "dissolution", date = D("1994-10-01"), source = "ISO 3166-3 comment"),
+  data.table(from_entity = "SKIN", to_entity = "IN", relation = "absorbed", date = D("1975-05-16"), source = "curated"),
+  data.table(from_entity = "PZPA", to_entity = "PA", relation = "absorbed", date = D("1979-10-01"), source = "curated"),
+  data.table(from_entity = "NTHH", to_entity = cldr_succ("NT"), relation = "dissolution", date = D("1991-12-26"), source = "CLDR territoryAlias NT"),
+  data.table(from_entity = "CTKI", to_entity = "KI", relation = "absorbed", date = D("1979-07-12"), source = "curated"),
+  data.table(from_entity = "CSH665", to_entity = c("IL", "PS"), relation = "partition", date = D("1948-05-14"), source = "curated"),
+  data.table(from_entity = "CSH3", to_entity = "US", relation = "absorbed", date = D("1959-01-03"), source = "curated"),
+  data.table(from_entity = "CSH4", to_entity = "US", relation = "absorbed", date = D("1959-08-21"), source = "curated"),
+  data.table(from_entity = "CSH21", to_entity = "CA", relation = "absorbed", date = D("1949-03-31"), source = "curated"),
+  data.table(from_entity = "CSH730", to_entity = c("KP", "KR"), relation = "partition", date = D("1945-08-15"), source = "curated"),
+  data.table(from_entity = "FQHH", to_entity = cldr_succ("FQ"), relation = "dissolution", date = D("1980-01-01"), source = "CLDR territoryAlias FQ"),
+  data.table(from_entity = "CSH291", to_entity = c("DE", "PL"), relation = "territory_to", date = D("1939-09-01"),
+             source = "curated: annexed by Germany 1939, part of Poland from 1945"),
+  data.table(from_entity = "CSH462", to_entity = "GH", relation = "absorbed", date = D("1957-03-06"),
+             source = "curated: joined the Gold Coast at Ghana's independence (outside the one-year geometry window)")
+))
+fwrite(lin, file.path(OUT, "history_curated_lineage.csv"))
+
+# ---- former codes -> entity -----------------------------------------------------
+iso3 <- as.data.table(fromJSON(file.path(SRC, "iso_3166-3.json"))[["3166-3"]])
+rename_to <- c(BYAA = "BY", BUMM = "MM", DYBJ = "BJ", HVBF = "BF", NHVU = "VU", RHZW = "ZW", TPTL = "TL", ZRCD = "CD",
+               AIDJ = "DJ", FXFR = "FR", VDVN = "VN", BQAQ = "AQ", NQAQ = "AQ", JTUM = "UM", MIUM = "UM", WKUM = "UM", PUUM = "UM")
+codes <- iso3[, .(code = alpha_4, code_type = "ISO 3166-3 alpha-4", name, withdrawn = withdrawal_date,
+                  entity_key = fifelse(alpha_4 %in% names(rename_to), rename_to[alpha_4], alpha_4))]
+codes <- rbind(codes, iso3[, .(code = alpha_2, code_type = "ISO 3166-1 alpha-2 (former)", name, withdrawn = withdrawal_date,
+                               entity_key = fifelse(alpha_4 %in% names(rename_to), rename_to[alpha_4], alpha_4))])
+fwrite(codes, file.path(OUT, "history_codes.csv"))   # filtered to known entities at build time
+
+# ---- names ------------------------------------------------------------------------
+# Names by which records refer to an entity, each with its source. Historical entities
+# get all four sources; current entities get only FORMER names (renames of a continuing
+# state), since their current names are already in the GNRS reference.
+curated_names <- rbindlist(list(
+  data.table(entity_key = "SUHH", name = c("USSR", "U.S.S.R.", "U.S.S.R", "Soviet Union", "SSSR", "CCCP", "UdSSR", "URSS",
+    "Union of Soviet Socialist Republics", "Former USSR", "Former U.S.S.R.", "Ex-USSR", "Ex USSR", "Former Soviet Union", "USSR (former)")),
+  data.table(entity_key = "YUCS", name = c("Yugoslavia", "Jugoslavija", "Jugoslawien", "Yougoslavie", "Yugoslavia (Former)",
+    "Former Yugoslavia", "Ex-Yugoslavia", "SFR Yugoslavia", "SFRY", "Socialist Federal Republic of Yugoslavia",
+    "Kingdom of Yugoslavia", "Kingdom of Serbs, Croats and Slovenes")),
+  data.table(entity_key = "CSXX", name = c("Serbia and Montenegro", "Serbia & Montenegro", "Federal Republic of Yugoslavia",
+    "FR Yugoslavia", "Srbija i Crna Gora")),
+  data.table(entity_key = "CSHH", name = c("Czechoslovakia", "Czecho-Slovakia", "Tschechoslowakei", "Tchécoslovaquie",
+    "Checoslovaquia", "ČSSR", "CSSR", "ČSR", "Czechoslovakia (Former)", "Former Czechoslovakia")),
+  data.table(entity_key = "DDDE", name = c("German Democratic Republic", "GDR", "DDR", "East Germany", "Germany, East",
+    "Deutsche Demokratische Republik", "RDA")),
+  data.table(entity_key = "YDYE", name = c("South Yemen", "People's Democratic Republic of Yemen", "Yemen, Democratic",
+    "Democratic Yemen", "PDR Yemen")),
+  data.table(entity_key = "VNRV", name = c("Republic of Vietnam", "South Vietnam", "Vietnam, South", "South Viet Nam")),
+  data.table(entity_key = "ANHH", name = c("Netherlands Antilles", "Nederlandse Antillen", "Antilles néerlandaises")),
+  data.table(entity_key = "RUBI", name = c("Ruanda-Urundi", "Ruanda Urundi")),
+  data.table(entity_key = "CSH665", name = c("Mandatory Palestine", "British Mandate of Palestine", "Palestine Mandate")),
+  data.table(entity_key = "CSH21", name = c("Newfoundland", "Dominion of Newfoundland")),
+  # former names of continuing states (rename rule): attach to the current entity
+  data.table(entity_key = "MM", name = c("Burma")),
+  data.table(entity_key = "CD", name = c("Zaire", "Zaïre", "Belgian Congo", "Congo (Kinshasa)", "Congo-Kinshasa")),
+  data.table(entity_key = "CG", name = c("Congo (Brazzaville)", "Congo-Brazzaville", "French Congo")),
+  data.table(entity_key = "BJ", name = c("Dahomey")),
+  data.table(entity_key = "BF", name = c("Upper Volta", "Haute-Volta")),
+  data.table(entity_key = "LK", name = c("Ceylon")),
+  data.table(entity_key = "TH", name = c("Siam")),
+  data.table(entity_key = "IR", name = c("Persia")),
+  data.table(entity_key = "BY", name = c("Byelorussia", "Belorussia", "Byelorussian SSR", "Belorussian SSR")),
+  data.table(entity_key = "ZW", name = c("Rhodesia", "Southern Rhodesia")),
+  data.table(entity_key = "ZM", name = c("Northern Rhodesia")),
+  data.table(entity_key = "MW", name = c("Nyasaland")),
+  data.table(entity_key = "LS", name = c("Basutoland")),
+  data.table(entity_key = "BW", name = c("Bechuanaland")),
+  data.table(entity_key = "GH", name = c("Gold Coast")),
+  data.table(entity_key = "ML", name = c("French Sudan")),
+  data.table(entity_key = "BZ", name = c("British Honduras")),
+  data.table(entity_key = "GY", name = c("British Guiana")),
+  data.table(entity_key = "SR", name = c("Dutch Guiana", "Netherlands Guiana")),
+  data.table(entity_key = "GQ", name = c("Spanish Guinea")),
+  data.table(entity_key = "ET", name = c("Abyssinia")),
+  data.table(entity_key = "KH", name = c("Kampuchea", "Khmer Republic")),
+  data.table(entity_key = "VU", name = c("New Hebrides")),
+  data.table(entity_key = "TL", name = c("East Timor", "Portuguese Timor")),
+  data.table(entity_key = "DJ", name = c("French Somaliland", "French Territory of the Afars and the Issas")),
+  data.table(entity_key = "TZ", name = c("Tanganyika")),
+  data.table(entity_key = "KI", name = c("Gilbert Islands")),
+  data.table(entity_key = "TV", name = c("Ellice Islands"))
+))
+curated_names[, source := "curated"]
+fwrite(curated_names, file.path(OUT, "history_curated_names.csv"))
+
+gn <- as.data.table(arrow::read_parquet(file.path(SRC, "geonames_political_features.parquet")))
+# only PCLH records of entities that can carry a GeoNames id: the curated historical
+# entities and the current countries (synthetic CShapes entities never have one)
+gn <- gn[feature_code == "PCLH" & geonameid %in% c(cur$geonameid, hist$geonameid, "7500737")]
+gn[geonameid == "7500737", geonameid := "8505033"]           # FR Yugoslavia -> CSXX entity
+gn_names <- gn[, .(name = unique(c(name, asciiname, trimws(strsplit(alternatenames, ",", fixed = TRUE)[[1]])))), by = geonameid]
+fwrite(gn_names[nzchar(name)], file.path(OUT, "history_geonames_names.csv"))   # joined to entities at build time
+
+# The rest - CShapes periods for uncurated codes, synthetic entities, coverage,
+# geometry-derived lineage, CShapes names and final assembly - runs at build time in
+# gnrs_history_assemble(). Remove the tables the previous version of this script wrote,
+# which were CShapes-derived and must not ship.
+unlink(file.path(OUT, c("history_entities.csv", "cshapes_entity_periods.csv",
+                        "history_lineage.csv", "history_names.csv")))
+cat(sprintf("curated: %d entities, %d periods, %d lineage links, %d names | GeoNames names: %d | codes: %d
+",
+            nrow(hist), nrow(curated_periods), nrow(lin), nrow(curated_names), nrow(gn_names[nzchar(name)]), nrow(codes)))
diff --git a/inst/extdata/SOURCES.md b/inst/extdata/SOURCES.md
new file mode 100644
index 0000000..c0f1239
--- /dev/null
+++ b/inst/extdata/SOURCES.md
@@ -0,0 +1,27 @@
+# Sources of the shipped history tables
+
+These tables are the *curated inputs* of the time-versioned division reference, written
+by `data-raw/history_crosswalk.R`. They are combined at build time with the user's own
+copy of CShapes 2.0 by `gnrs_history_assemble()`.
+
+**Nothing derived from CShapes 2.0 ships with this package.** CShapes is licensed
+CC BY-NC-SA 4.0 and this package is MIT, so every CShapes-derived part of the history
+component (periods of uncurated state codes, synthetic `CSH<gwcode>` entities and their
+names, the coverage check, and geometry-derived lineage) is computed in the user's cache
+from CShapes obtained under its own licence. `CSH<gwcode>` keys that appear below are
+identifiers only, for entities whose names and dates were curated by hand.
+
+| File | Content | Source and licence |
+|---|---|---|
+| `history_current_entities.csv` | snapshot of the service's current countries | GNRS country table; names and ids from GeoNames (CC BY 4.0) |
+| `history_curated_entities.csv` | historical entities and their dates | curated for GNRS (MIT) |
+| `history_curated_periods.csv` | assignments of CShapes state codes to entities over periods | curated for GNRS (MIT) |
+| `history_curated_lineage.csv` | predecessor -> successor links | curated for GNRS (MIT); successor lists from Unicode CLDR `territoryAlias` (Unicode License v3) |
+| `history_curated_names.csv` | curated names and former names | curated for GNRS (MIT) |
+| `history_geonames_names.csv` | names of historical political entities (feature code PCLH) | GeoNames, https://www.geonames.org/ (CC BY 4.0) |
+| `history_codes.csv` | former country codes and the entity each denotes | ISO 3166-3 via Debian iso-codes (LGPL-2.1+); mapping to entities curated for GNRS |
+
+When the history component is built, `GNRS_local_citations()` also cites CShapes 2.0:
+Schvitz G., Girardin L., Ruegger S., Weidmann N. B., Cederman L.-E. & Gleditsch K. S.
+(2022). Mapping the International System, 1886-2019: The CShapes 2.0 Dataset. *Journal of
+Conflict Resolution* 66(1): 144-161. https://doi.org/10.1177/00220027211013563
diff --git a/inst/extdata/altdiv_extent.csv b/inst/extdata/altdiv_extent.csv
new file mode 100644
index 0000000..86cbe3c
--- /dev/null
+++ b/inst/extdata/altdiv_extent.csv
@@ -0,0 +1,37 @@
+entity_key,level,gid
+NO-TRONDELAG,1,NOR.9_1
+NO-TRONDELAG,1,NOR.15_1
+NO-VIKEN,1,NOR.1_1
+NO-VIKEN,1,NOR.4_1
+NO-VIKEN,1,NOR.2_1
+NO-INNLANDET,1,NOR.6_1
+NO-INNLANDET,1,NOR.11_1
+NO-VESTLAND,1,NOR.7_1
+NO-VESTLAND,1,NOR.14_1
+NO-VESTFOLD-TELEMARK,1,NOR.19_1
+NO-VESTFOLD-TELEMARK,1,NOR.16_1
+NO-TROMS-FINNMARK,1,NOR.17_1
+NO-TROMS-FINNMARK,1,NOR.5_1
+NO-AGDER,1,NOR.3_1
+NO-AGDER,1,NOR.18_1
+SE-LAN-SWE.1_1,1,SWE.1_1
+SE-LAN-SWE.10_1,1,SWE.10_1
+SE-LAN-SWE.11_1,1,SWE.11_1
+SE-LAN-SWE.12_1,1,SWE.12_1
+SE-LAN-SWE.13_1,1,SWE.13_1
+SE-LAN-SWE.14_1,1,SWE.14_1
+SE-LAN-SWE.15_1,1,SWE.15_1
+SE-LAN-SWE.16_1,1,SWE.16_1
+SE-LAN-SWE.17_1,1,SWE.17_1
+SE-LAN-SWE.18_1,1,SWE.18_1
+SE-LAN-SWE.19_1,1,SWE.19_1
+SE-LAN-SWE.2_1,1,SWE.2_1
+SE-LAN-SWE.20_1,1,SWE.20_1
+SE-LAN-SWE.21_1,1,SWE.21_1
+SE-LAN-SWE.3_1,1,SWE.3_1
+SE-LAN-SWE.4_1,1,SWE.4_1
+SE-LAN-SWE.5_1,1,SWE.5_1
+SE-LAN-SWE.6_1,1,SWE.6_1
+SE-LAN-SWE.7_1,1,SWE.7_1
+SE-LAN-SWE.8_1,1,SWE.8_1
+SE-LAN-SWE.9_1,1,SWE.9_1
diff --git a/inst/extdata/altdiv_names.csv b/inst/extdata/altdiv_names.csv
new file mode 100644
index 0000000..3e35aa4
--- /dev/null
+++ b/inst/extdata/altdiv_names.csv
@@ -0,0 +1,103 @@
+entity_key,name,match
+NO-TRONDELAG,Trøndelag,exact
+NO-VIKEN,Viken,exact
+NO-INNLANDET,Innlandet,exact
+NO-VESTLAND,Vestland,exact
+NO-VESTFOLD-TELEMARK,Vestfold og Telemark,exact
+NO-TROMS-FINNMARK,Troms og Finnmark,exact
+NO-AGDER,Agder,exact
+SE-LAN-SWE.1_1,Blekinge,exact
+SE-LAN-SWE.1_1,Blekinge län,exact
+SE-LAN-SWE.1_1,Blekinges län,exact
+SE-LAN-SWE.10_1,Norrbotten,exact
+SE-LAN-SWE.10_1,Norrbotten län,exact
+SE-LAN-SWE.10_1,Norrbottens län,exact
+SE-LAN-SWE.11_1,Orebro,exact
+SE-LAN-SWE.11_1,Orebro län,exact
+SE-LAN-SWE.11_1,Orebros län,exact
+SE-LAN-SWE.12_1,Östergötland,exact
+SE-LAN-SWE.12_1,Östergötland län,exact
+SE-LAN-SWE.12_1,Östergötlands län,exact
+SE-LAN-SWE.13_1,Skåne,exact
+SE-LAN-SWE.13_1,Skåne län,exact
+SE-LAN-SWE.13_1,Skånes län,exact
+SE-LAN-SWE.14_1,Södermanland,exact
+SE-LAN-SWE.14_1,Södermanland län,exact
+SE-LAN-SWE.14_1,Södermanlands län,exact
+SE-LAN-SWE.15_1,Stockholm,exact
+SE-LAN-SWE.15_1,Stockholm län,exact
+SE-LAN-SWE.15_1,Stockholms län,exact
+SE-LAN-SWE.16_1,Uppsala,exact
+SE-LAN-SWE.16_1,Uppsala län,exact
+SE-LAN-SWE.16_1,Uppsalas län,exact
+SE-LAN-SWE.17_1,Värmland,exact
+SE-LAN-SWE.17_1,Värmland län,exact
+SE-LAN-SWE.17_1,Värmlands län,exact
+SE-LAN-SWE.18_1,Västerbotten,exact
+SE-LAN-SWE.18_1,Västerbotten län,exact
+SE-LAN-SWE.18_1,Västerbottens län,exact
+SE-LAN-SWE.19_1,Västernorrland,exact
+SE-LAN-SWE.19_1,Västernorrland län,exact
+SE-LAN-SWE.19_1,Västernorrlands län,exact
+SE-LAN-SWE.2_1,Dalarna,exact
+SE-LAN-SWE.2_1,Dalarna län,exact
+SE-LAN-SWE.2_1,Dalarnas län,exact
+SE-LAN-SWE.20_1,Västmanland,exact
+SE-LAN-SWE.20_1,Västmanland län,exact
+SE-LAN-SWE.20_1,Västmanlands län,exact
+SE-LAN-SWE.21_1,Västra Götaland,exact
+SE-LAN-SWE.21_1,Västra Götaland län,exact
+SE-LAN-SWE.21_1,Västra Götalands län,exact
+SE-LAN-SWE.3_1,Gävleborg,exact
+SE-LAN-SWE.3_1,Gävleborg län,exact
+SE-LAN-SWE.3_1,Gävleborgs län,exact
+SE-LAN-SWE.4_1,Gotland,exact
+SE-LAN-SWE.4_1,Gotland län,exact
+SE-LAN-SWE.4_1,Gotlands län,exact
+SE-LAN-SWE.5_1,Halland,exact
+SE-LAN-SWE.5_1,Halland län,exact
+SE-LAN-SWE.5_1,Hallands län,exact
+SE-LAN-SWE.6_1,Jämtland,exact
+SE-LAN-SWE.6_1,Jämtland län,exact
+SE-LAN-SWE.6_1,Jämtlands län,exact
+SE-LAN-SWE.7_1,Jönköping,exact
+SE-LAN-SWE.7_1,Jönköping län,exact
+SE-LAN-SWE.7_1,Jönköpings län,exact
+SE-LAN-SWE.8_1,Kalmar,exact
+SE-LAN-SWE.8_1,Kalmar län,exact
+SE-LAN-SWE.8_1,Kalmars län,exact
+SE-LAN-SWE.9_1,Kronoberg,exact
+SE-LAN-SWE.9_1,Kronoberg län,exact
+SE-LAN-SWE.9_1,Kronobergs län,exact
+SE-LS-Blekinge,Blekinge,exact
+SE-LS-Bohuslan,Bohuslän,exact
+SE-LS-Dalarna,Dalarna,exact
+SE-LS-Dalsland,Dalsland,exact
+SE-LS-Gotland,Gotland,exact
+SE-LS-Gastrikland,Gästrikland,exact
+SE-LS-Halland,Halland,exact
+SE-LS-Halsingland,Hälsingland,exact
+SE-LS-Harjedalen,Härjedalen,exact
+SE-LS-Jamtland,Jämtland,exact
+SE-LS-Lappland,Lappland,exact
+SE-LS-Medelpad,Medelpad,exact
+SE-LS-Norrbotten,Norrbotten,exact
+SE-LS-Narke,Närke,exact
+SE-LS-Skane,Skåne,exact
+SE-LS-Smaland,Småland,exact
+SE-LS-Sodermanland,Södermanland,exact
+SE-LS-Uppland,Uppland,exact
+SE-LS-Varmland,Värmland,exact
+SE-LS-Vasterbotten,Västerbotten,exact
+SE-LS-Vastergotland,Västergötland,exact
+SE-LS-Vastmanland,Västmanland,exact
+SE-LS-Angermanland,Ångermanland,exact
+SE-LS-Oland,Öland,exact
+SE-LS-Ostergotland,Östergötland,exact
+SE-LP-Lule,Lule lappmark,exact
+SE-LP-Lycksele,Lycksele lappmark,exact
+SE-LP-Pite,Pite lappmark,exact
+SE-LP-Torne,Torne lappmark,exact
+SE-LP-Asele,Åsele lappmark,exact
+GB-VC,^VC ?[0-9]+,regex
+IE-VC,^VC ?[0-9]+,regex
diff --git a/inst/extdata/altdiv_units.csv b/inst/extdata/altdiv_units.csv
new file mode 100644
index 0000000..f6a2fd0
--- /dev/null
+++ b/inst/extdata/altdiv_units.csv
@@ -0,0 +1,61 @@
+system,entity_key,country_iso,name,kind,valid_from,valid_to,note
+no-fylke,NO-TRONDELAG,NO,Trøndelag,superseded,2018-01-01,,2018 merger of Nord-Trøndelag and Sør-Trøndelag
+no-fylke,NO-VIKEN,NO,Viken,superseded,2020-01-01,2023-12-31,"Akershus, Buskerud and Østfold; dissolved 2024-01-01"
+no-fylke,NO-INNLANDET,NO,Innlandet,superseded,2020-01-01,,Hedmark and Oppland
+no-fylke,NO-VESTLAND,NO,Vestland,superseded,2020-01-01,,Hordaland and Sogn og Fjordane
+no-fylke,NO-VESTFOLD-TELEMARK,NO,Vestfold og Telemark,superseded,2020-01-01,2023-12-31,Vestfold and Telemark; dissolved 2024-01-01
+no-fylke,NO-TROMS-FINNMARK,NO,Troms og Finnmark,superseded,2020-01-01,2023-12-31,Troms and Finnmark; dissolved 2024-01-01
+no-fylke,NO-AGDER,NO,Agder,superseded,2020-01-01,,Aust-Agder and Vest-Agder
+se-lan-alias,SE-LAN-SWE.1_1,SE,Blekinge,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.10_1,SE,Norrbotten,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.11_1,SE,Orebro,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.12_1,SE,Östergötland,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.13_1,SE,Skåne,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.14_1,SE,Södermanland,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.15_1,SE,Stockholm,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.16_1,SE,Uppsala,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.17_1,SE,Värmland,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.18_1,SE,Västerbotten,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.19_1,SE,Västernorrland,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.2_1,SE,Dalarna,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.20_1,SE,Västmanland,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.21_1,SE,Västra Götaland,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.3_1,SE,Gävleborg,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.4_1,SE,Gotland,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.5_1,SE,Halland,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.6_1,SE,Jämtland,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.7_1,SE,Jönköping,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.8_1,SE,Kalmar,alias,,,the same GADM unit under the name records use
+se-lan-alias,SE-LAN-SWE.9_1,SE,Kronoberg,alias,,,the same GADM unit under the name records use
+se-landskap,SE-LS-Blekinge,SE,Blekinge,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Bohuslan,SE,Bohuslän,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Dalarna,SE,Dalarna,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Dalsland,SE,Dalsland,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Gotland,SE,Gotland,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Gastrikland,SE,Gästrikland,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Halland,SE,Halland,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Halsingland,SE,Hälsingland,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Harjedalen,SE,Härjedalen,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Jamtland,SE,Jämtland,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Lappland,SE,Lappland,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Medelpad,SE,Medelpad,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Norrbotten,SE,Norrbotten,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Narke,SE,Närke,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Skane,SE,Skåne,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Smaland,SE,Småland,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Sodermanland,SE,Södermanland,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Uppland,SE,Uppland,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Varmland,SE,Värmland,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Vasterbotten,SE,Västerbotten,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Vastergotland,SE,Västergötland,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Vastmanland,SE,Västmanland,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Angermanland,SE,Ångermanland,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Oland,SE,Öland,parallel,,,landskap (province); extent not yet sourced
+se-landskap,SE-LS-Ostergotland,SE,Östergötland,parallel,,,landskap (province); extent not yet sourced
+se-lappmark,SE-LP-Lule,SE,Lule lappmark,parallel,,,lappmark; extent not yet sourced
+se-lappmark,SE-LP-Lycksele,SE,Lycksele lappmark,parallel,,,lappmark; extent not yet sourced
+se-lappmark,SE-LP-Pite,SE,Pite lappmark,parallel,,,lappmark; extent not yet sourced
+se-lappmark,SE-LP-Torne,SE,Torne lappmark,parallel,,,lappmark; extent not yet sourced
+se-lappmark,SE-LP-Asele,SE,Åsele lappmark,parallel,,,lappmark; extent not yet sourced
+gb-vice-county,GB-VC,GB,Watsonian vice-county,parallel,,,"botanical recording unit, boundaries frozen at 1852; extent not yet sourced"
+gb-vice-county,IE-VC,IE,Watsonian vice-county,parallel,,,"botanical recording unit, boundaries frozen at 1852; extent not yet sourced"
diff --git a/inst/extdata/history_codes.csv b/inst/extdata/history_codes.csv
new file mode 100644
index 0000000..46f9628
--- /dev/null
+++ b/inst/extdata/history_codes.csv
@@ -0,0 +1,63 @@
+code,code_type,name,withdrawn,entity_key
+AIDJ,ISO 3166-3 alpha-4,French Afars and Issas,1977,DJ
+ANHH,ISO 3166-3 alpha-4,Netherlands Antilles,2010-12-15,ANHH
+BQAQ,ISO 3166-3 alpha-4,British Antarctic Territory,1979,AQ
+BUMM,ISO 3166-3 alpha-4,"Burma, Socialist Republic of the Union of",1989-12-05,MM
+BYAA,ISO 3166-3 alpha-4,Byelorussian SSR Soviet Socialist Republic,1992-06-15,BY
+CSHH,ISO 3166-3 alpha-4,"Czechoslovakia, Czechoslovak Socialist Republic",1993-06-15,CSHH
+CSXX,ISO 3166-3 alpha-4,Serbia and Montenegro,2006-09-26,CSXX
+CTKI,ISO 3166-3 alpha-4,Canton and Enderbury Islands,1984,CTKI
+DDDE,ISO 3166-3 alpha-4,German Democratic Republic,1990-10-30,DDDE
+DYBJ,ISO 3166-3 alpha-4,Dahomey,1977,BJ
+FQHH,ISO 3166-3 alpha-4,French Southern and Antarctic Territories,1979,FQHH
+FXFR,ISO 3166-3 alpha-4,"France, Metropolitan",1997-07-14,FR
+GEHH,ISO 3166-3 alpha-4,Gilbert and Ellice Islands,1979,GEHH
+HVBF,ISO 3166-3 alpha-4,"Upper Volta, Republic of",1984,BF
+JTUM,ISO 3166-3 alpha-4,Johnston Island,1986,UM
+MIUM,ISO 3166-3 alpha-4,Midway Islands,1986,UM
+NHVU,ISO 3166-3 alpha-4,New Hebrides,1980,VU
+NQAQ,ISO 3166-3 alpha-4,Dronning Maud Land,1983,AQ
+NTHH,ISO 3166-3 alpha-4,Neutral Zone,1993-07-12,NTHH
+PCHH,ISO 3166-3 alpha-4,Pacific Islands (trust territory),1986,PCHH
+PUUM,ISO 3166-3 alpha-4,US Miscellaneous Pacific Islands,1986,UM
+PZPA,ISO 3166-3 alpha-4,Panama Canal Zone,1980,PZPA
+RHZW,ISO 3166-3 alpha-4,Southern Rhodesia,1980,ZW
+SKIN,ISO 3166-3 alpha-4,Sikkim,1975,SKIN
+SUHH,ISO 3166-3 alpha-4,"USSR, Union of Soviet Socialist Republics",1992-08-30,SUHH
+TPTL,ISO 3166-3 alpha-4,East Timor,2002-05-20,TL
+VDVN,ISO 3166-3 alpha-4,"Viet-Nam, Democratic Republic of",1977,VN
+WKUM,ISO 3166-3 alpha-4,Wake Island,1986,UM
+YDYE,ISO 3166-3 alpha-4,"Yemen, Democratic, People's Democratic Republic of",1990-08-14,YDYE
+YUCS,ISO 3166-3 alpha-4,"Yugoslavia, (Socialist) Federal Republic of",2003-07-23,YUCS
+ZRCD,ISO 3166-3 alpha-4,"Zaire, Republic of",1997-07-14,CD
+AI,ISO 3166-1 alpha-2 (former),French Afars and Issas,1977,DJ
+AN,ISO 3166-1 alpha-2 (former),Netherlands Antilles,2010-12-15,ANHH
+BQ,ISO 3166-1 alpha-2 (former),British Antarctic Territory,1979,AQ
+BU,ISO 3166-1 alpha-2 (former),"Burma, Socialist Republic of the Union of",1989-12-05,MM
+BY,ISO 3166-1 alpha-2 (former),Byelorussian SSR Soviet Socialist Republic,1992-06-15,BY
+CS,ISO 3166-1 alpha-2 (former),"Czechoslovakia, Czechoslovak Socialist Republic",1993-06-15,CSHH
+CS,ISO 3166-1 alpha-2 (former),Serbia and Montenegro,2006-09-26,CSXX
+CT,ISO 3166-1 alpha-2 (former),Canton and Enderbury Islands,1984,CTKI
+DD,ISO 3166-1 alpha-2 (former),German Democratic Republic,1990-10-30,DDDE
+DY,ISO 3166-1 alpha-2 (former),Dahomey,1977,BJ
+FQ,ISO 3166-1 alpha-2 (former),French Southern and Antarctic Territories,1979,FQHH
+FX,ISO 3166-1 alpha-2 (former),"France, Metropolitan",1997-07-14,FR
+GE,ISO 3166-1 alpha-2 (former),Gilbert and Ellice Islands,1979,GEHH
+HV,ISO 3166-1 alpha-2 (former),"Upper Volta, Republic of",1984,BF
+JT,ISO 3166-1 alpha-2 (former),Johnston Island,1986,UM
+MI,ISO 3166-1 alpha-2 (former),Midway Islands,1986,UM
+NH,ISO 3166-1 alpha-2 (former),New Hebrides,1980,VU
+NQ,ISO 3166-1 alpha-2 (former),Dronning Maud Land,1983,AQ
+NT,ISO 3166-1 alpha-2 (former),Neutral Zone,1993-07-12,NTHH
+PC,ISO 3166-1 alpha-2 (former),Pacific Islands (trust territory),1986,PCHH
+PU,ISO 3166-1 alpha-2 (former),US Miscellaneous Pacific Islands,1986,UM
+PZ,ISO 3166-1 alpha-2 (former),Panama Canal Zone,1980,PZPA
+RH,ISO 3166-1 alpha-2 (former),Southern Rhodesia,1980,ZW
+SK,ISO 3166-1 alpha-2 (former),Sikkim,1975,SKIN
+SU,ISO 3166-1 alpha-2 (former),"USSR, Union of Soviet Socialist Republics",1992-08-30,SUHH
+TP,ISO 3166-1 alpha-2 (former),East Timor,2002-05-20,TL
+VD,ISO 3166-1 alpha-2 (former),"Viet-Nam, Democratic Republic of",1977,VN
+WK,ISO 3166-1 alpha-2 (former),Wake Island,1986,UM
+YD,ISO 3166-1 alpha-2 (former),"Yemen, Democratic, People's Democratic Republic of",1990-08-14,YDYE
+YU,ISO 3166-1 alpha-2 (former),"Yugoslavia, (Socialist) Federal Republic of",2003-07-23,YUCS
+ZR,ISO 3166-1 alpha-2 (former),"Zaire, Republic of",1997-07-14,CD
diff --git a/inst/extdata/history_curated_entities.csv b/inst/extdata/history_curated_entities.csv
new file mode 100644
index 0000000..cd0be58
--- /dev/null
+++ b/inst/extdata/history_curated_entities.csv
@@ -0,0 +1,22 @@
+entity_key,name,geonameid,iso3166_1,iso3166_3,valid_from,valid_to,kind,note
+SUHH,Union of Soviet Socialist Republics,8354411,,SUHH,1922-12-30,1991-12-25,historical,Treaty on the Creation of the USSR to dissolution
+CSHH,Czechoslovakia,8505031,,CSHH,1918-10-28,1992-12-31,historical,including the Czechoslovak Socialist Republic
+DDDE,German Democratic Republic,8354410,,DDDE,1949-10-07,1990-10-02,historical,absorbed by the Federal Republic of Germany
+YUCS,"Yugoslavia (Kingdom of Serbs, Croats and Slovenes; Kingdom of Yugoslavia; SFR Yugoslavia)",,,YUCS,1918-12-01,1992-04-26,historical,"no GeoNames PCLH; ISO YUCS also covered FR Yugoslavia, modelled separately as CSXX"
+CSXX,Serbia and Montenegro (Federal Republic of Yugoslavia to 2003),8505033,,CSXX,1992-04-27,2006-06-03,historical,GeoNames also has FR Yugoslavia as 7500737; one state renamed in 2003
+YDYE,People's Democratic Republic of Yemen,8505034,,YDYE,1967-11-30,1990-05-21,historical,merged with the Yemen Arab Republic
+VNRV,Republic of Vietnam,11608491,,,1955-10-26,1975-04-30,historical,synthetic key; absorbed into Vietnam
+ANHH,Netherlands Antilles,8505032,,ANHH,1954-12-15,2010-10-09,historical,Aruba separated 1986
+RUBI,Ruanda-Urundi,11612757,,,1922-07-20,1962-06-30,historical,synthetic key; Belgian mandate
+GEHH,Gilbert and Ellice Islands,,,GEHH,1892-05-27,1975-12-31,historical,split into Kiribati and Tuvalu
+PCHH,Trust Territory of the Pacific Islands,,,PCHH,1947-07-18,1994-10-01,historical,"divided into FM, MH, MP and PW"
+SKIN,Sikkim,,,SKIN,1642-01-01,1975-05-16,historical,absorbed by India
+PZPA,Panama Canal Zone,,,PZPA,1903-11-18,1979-09-30,historical,returned to Panama
+NTHH,Saudi Arabian-Iraqi Neutral Zone,,,NTHH,1922-12-02,1991-12-26,historical,divided between SA and IQ
+CTKI,Canton and Enderbury Islands,,,CTKI,1939-04-06,1979-07-12,historical,to Kiribati
+FQHH,French Southern and Antarctic Territories (former code),,,FQHH,,1979-12-31,historical,now AQ and TF
+CSH665,Mandatory Palestine,,,,1920-04-26,1948-05-14,historical,synthetic key from CShapes 665
+CSH3,Territory of Alaska,,,,1867-10-18,1959-01-02,historical,US territory; a US state since 1959
+CSH4,Territory of Hawaii,,,,1898-07-07,1959-08-20,historical,US territory; a US state since 1959
+CSH21,Dominion of Newfoundland,,,,1907-09-26,1949-03-31,historical,joined Canada
+CSH730,Korea (before partition),,,,,1945-08-14,historical,Korean Empire / Japanese Korea; successors KP and KR
diff --git a/inst/extdata/history_curated_lineage.csv b/inst/extdata/history_curated_lineage.csv
new file mode 100644
index 0000000..2fe0b10
--- /dev/null
+++ b/inst/extdata/history_curated_lineage.csv
@@ -0,0 +1,58 @@
+from_entity,to_entity,relation,date,source
+SUHH,RU,dissolution,1991-12-26,CLDR territoryAlias SU
+SUHH,AM,dissolution,1991-12-26,CLDR territoryAlias SU
+SUHH,AZ,dissolution,1991-12-26,CLDR territoryAlias SU
+SUHH,BY,dissolution,1991-12-26,CLDR territoryAlias SU
+SUHH,EE,dissolution,1991-12-26,CLDR territoryAlias SU
+SUHH,GE,dissolution,1991-12-26,CLDR territoryAlias SU
+SUHH,KZ,dissolution,1991-12-26,CLDR territoryAlias SU
+SUHH,KG,dissolution,1991-12-26,CLDR territoryAlias SU
+SUHH,LV,dissolution,1991-12-26,CLDR territoryAlias SU
+SUHH,LT,dissolution,1991-12-26,CLDR territoryAlias SU
+SUHH,MD,dissolution,1991-12-26,CLDR territoryAlias SU
+SUHH,TJ,dissolution,1991-12-26,CLDR territoryAlias SU
+SUHH,TM,dissolution,1991-12-26,CLDR territoryAlias SU
+SUHH,UA,dissolution,1991-12-26,CLDR territoryAlias SU
+SUHH,UZ,dissolution,1991-12-26,CLDR territoryAlias SU
+CSHH,CZ,dissolution,1993-01-01,CLDR territoryAlias 200
+CSHH,SK,dissolution,1993-01-01,CLDR territoryAlias 200
+DDDE,DE,absorbed,1990-10-03,CLDR territoryAlias DD
+YDYE,YE,merged,1990-05-22,CLDR territoryAlias YD
+YUCS,SI,dissolution,1992-04-27,"CLDR territoryAlias 890 (RS ME replaced by CSXX, their direct predecessor)"
+YUCS,HR,dissolution,1992-04-27,"CLDR territoryAlias 890 (RS ME replaced by CSXX, their direct predecessor)"
+YUCS,MK,dissolution,1992-04-27,"CLDR territoryAlias 890 (RS ME replaced by CSXX, their direct predecessor)"
+YUCS,BA,dissolution,1992-04-27,"CLDR territoryAlias 890 (RS ME replaced by CSXX, their direct predecessor)"
+YUCS,CSXX,dissolution,1992-04-27,"CLDR territoryAlias 890 (RS ME replaced by CSXX, their direct predecessor)"
+CSXX,RS,dissolution,2006-06-03,CLDR territoryAlias CS
+CSXX,ME,dissolution,2006-06-03,CLDR territoryAlias CS
+RS,XK,secession,2008-02-17,curated
+ANHH,CW,dissolution,2010-10-10,CLDR territoryAlias AN
+ANHH,SX,dissolution,2010-10-10,CLDR territoryAlias AN
+ANHH,BQ,dissolution,2010-10-10,CLDR territoryAlias AN
+ANHH,AW,secession,1986-01-01,curated (ISO 3166-3 comment)
+VNRV,VN,absorbed,1976-07-02,curated
+RUBI,RW,dissolution,1962-07-01,curated
+RUBI,BI,dissolution,1962-07-01,curated
+GEHH,KI,dissolution,1976-01-01,ISO 3166-3 comment
+GEHH,TV,dissolution,1976-01-01,ISO 3166-3 comment
+PCHH,FM,dissolution,1994-10-01,ISO 3166-3 comment
+PCHH,MH,dissolution,1994-10-01,ISO 3166-3 comment
+PCHH,MP,dissolution,1994-10-01,ISO 3166-3 comment
+PCHH,PW,dissolution,1994-10-01,ISO 3166-3 comment
+SKIN,IN,absorbed,1975-05-16,curated
+PZPA,PA,absorbed,1979-10-01,curated
+NTHH,SA,dissolution,1991-12-26,CLDR territoryAlias NT
+NTHH,IQ,dissolution,1991-12-26,CLDR territoryAlias NT
+CTKI,KI,absorbed,1979-07-12,curated
+CSH665,IL,partition,1948-05-14,curated
+CSH665,PS,partition,1948-05-14,curated
+CSH3,US,absorbed,1959-01-03,curated
+CSH4,US,absorbed,1959-08-21,curated
+CSH21,CA,absorbed,1949-03-31,curated
+CSH730,KP,partition,1945-08-15,curated
+CSH730,KR,partition,1945-08-15,curated
+FQHH,AQ,dissolution,1980-01-01,CLDR territoryAlias FQ
+FQHH,TF,dissolution,1980-01-01,CLDR territoryAlias FQ
+CSH291,DE,territory_to,1939-09-01,"curated: annexed by Germany 1939, part of Poland from 1945"
+CSH291,PL,territory_to,1939-09-01,"curated: annexed by Germany 1939, part of Poland from 1945"
+CSH462,GH,absorbed,1957-03-06,curated: joined the Gold Coast at Ghana's independence (outside the one-year geometry window)
diff --git a/inst/extdata/history_curated_names.csv b/inst/extdata/history_curated_names.csv
new file mode 100644
index 0000000..b94c60e
--- /dev/null
+++ b/inst/extdata/history_curated_names.csv
@@ -0,0 +1,112 @@
+entity_key,name,source
+SUHH,USSR,curated
+SUHH,U.S.S.R.,curated
+SUHH,U.S.S.R,curated
+SUHH,Soviet Union,curated
+SUHH,SSSR,curated
+SUHH,CCCP,curated
+SUHH,UdSSR,curated
+SUHH,URSS,curated
+SUHH,Union of Soviet Socialist Republics,curated
+SUHH,Former USSR,curated
+SUHH,Former U.S.S.R.,curated
+SUHH,Ex-USSR,curated
+SUHH,Ex USSR,curated
+SUHH,Former Soviet Union,curated
+SUHH,USSR (former),curated
+YUCS,Yugoslavia,curated
+YUCS,Jugoslavija,curated
+YUCS,Jugoslawien,curated
+YUCS,Yougoslavie,curated
+YUCS,Yugoslavia (Former),curated
+YUCS,Former Yugoslavia,curated
+YUCS,Ex-Yugoslavia,curated
+YUCS,SFR Yugoslavia,curated
+YUCS,SFRY,curated
+YUCS,Socialist Federal Republic of Yugoslavia,curated
+YUCS,Kingdom of Yugoslavia,curated
+YUCS,"Kingdom of Serbs, Croats and Slovenes",curated
+CSXX,Serbia and Montenegro,curated
+CSXX,Serbia & Montenegro,curated
+CSXX,Federal Republic of Yugoslavia,curated
+CSXX,FR Yugoslavia,curated
+CSXX,Srbija i Crna Gora,curated
+CSHH,Czechoslovakia,curated
+CSHH,Czecho-Slovakia,curated
+CSHH,Tschechoslowakei,curated
+CSHH,Tchécoslovaquie,curated
+CSHH,Checoslovaquia,curated
+CSHH,ČSSR,curated
+CSHH,CSSR,curated
+CSHH,ČSR,curated
+CSHH,Czechoslovakia (Former),curated
+CSHH,Former Czechoslovakia,curated
+DDDE,German Democratic Republic,curated
+DDDE,GDR,curated
+DDDE,DDR,curated
+DDDE,East Germany,curated
+DDDE,"Germany, East",curated
+DDDE,Deutsche Demokratische Republik,curated
+DDDE,RDA,curated
+YDYE,South Yemen,curated
+YDYE,People's Democratic Republic of Yemen,curated
+YDYE,"Yemen, Democratic",curated
+YDYE,Democratic Yemen,curated
+YDYE,PDR Yemen,curated
+VNRV,Republic of Vietnam,curated
+VNRV,South Vietnam,curated
+VNRV,"Vietnam, South",curated
+VNRV,South Viet Nam,curated
+ANHH,Netherlands Antilles,curated
+ANHH,Nederlandse Antillen,curated
+ANHH,Antilles néerlandaises,curated
+RUBI,Ruanda-Urundi,curated
+RUBI,Ruanda Urundi,curated
+CSH665,Mandatory Palestine,curated
+CSH665,British Mandate of Palestine,curated
+CSH665,Palestine Mandate,curated
+CSH21,Newfoundland,curated
+CSH21,Dominion of Newfoundland,curated
+MM,Burma,curated
+CD,Zaire,curated
+CD,Zaïre,curated
+CD,Belgian Congo,curated
+CD,Congo (Kinshasa),curated
+CD,Congo-Kinshasa,curated
+CG,Congo (Brazzaville),curated
+CG,Congo-Brazzaville,curated
+CG,French Congo,curated
+BJ,Dahomey,curated
+BF,Upper Volta,curated
+BF,Haute-Volta,curated
+LK,Ceylon,curated
+TH,Siam,curated
+IR,Persia,curated
+BY,Byelorussia,curated
+BY,Belorussia,curated
+BY,Byelorussian SSR,curated
+BY,Belorussian SSR,curated
+ZW,Rhodesia,curated
+ZW,Southern Rhodesia,curated
+ZM,Northern Rhodesia,curated
+MW,Nyasaland,curated
+LS,Basutoland,curated
+BW,Bechuanaland,curated
+GH,Gold Coast,curated
+ML,French Sudan,curated
+BZ,British Honduras,curated
+GY,British Guiana,curated
+SR,Dutch Guiana,curated
+SR,Netherlands Guiana,curated
+GQ,Spanish Guinea,curated
+ET,Abyssinia,curated
+KH,Kampuchea,curated
+KH,Khmer Republic,curated
+VU,New Hebrides,curated
+TL,East Timor,curated
+TL,Portuguese Timor,curated
+DJ,French Somaliland,curated
+DJ,French Territory of the Afars and the Issas,curated
+TZ,Tanganyika,curated
+KI,Gilbert Islands,curated
+TV,Ellice Islands,curated
diff --git a/inst/extdata/history_curated_periods.csv b/inst/extdata/history_curated_periods.csv
new file mode 100644
index 0000000..2797131
--- /dev/null
+++ b/inst/extdata/history_curated_periods.csv
@@ -0,0 +1,30 @@
+gwcode,from,to,entity_key,note,basis
+365,1886-01-01,1922-12-29,RU,Russian Empire and Soviet Russia: same continuing state as the Russian Federation (rename rule),curated
+365,1922-12-30,1991-12-25,SUHH,USSR,curated
+365,1991-12-26,2019-12-31,RU,Russian Federation,curated
+345,1918-12-01,1992-04-26,YUCS,Yugoslavia to the break-up,curated
+345,1992-04-27,2006-06-02,CSXX,FR Yugoslavia / Serbia and Montenegro,curated
+265,1945-05-08,1990-10-02,DDDE,CShapes starts the unit at the Soviet occupation zone (1945); the GDR was founded 1949-10-07,curated
+315,1918-11-11,1992-12-31,CSHH,Czechoslovakia,curated
+680,1967-11-30,1990-05-21,YDYE,South Yemen,curated
+678,1918-10-30,2019-12-31,YE,Yemen Arab Republic continues as Yemen after unification (ISO YE retained),curated
+816,1954-05-01,2019-12-31,VN,Democratic Republic of Vietnam continues as Vietnam (rename rule),curated
+817,1954-05-01,1975-04-30,VNRV,Republic of Vietnam,curated
+515,1920-06-28,1962-06-30,RUBI,Ruanda-Urundi,curated
+255,1886-01-01,1945-05-07,DE,German Empire / Reich: same continuing state as Germany (rename rule),curated
+6,1886-01-01,2019-12-31,PR,territory still exists,curated
+65,1886-01-01,2019-12-31,GP,territory still exists,curated
+66,1886-01-01,2019-12-31,MQ,territory still exists,curated
+120,1886-01-01,2019-12-31,GF,territory still exists,curated
+585,1886-01-01,2019-12-31,RE,territory still exists,curated
+930,1886-01-01,2019-12-31,NC,territory still exists,curated
+960,1903-05-19,2019-12-31,PF,territory still exists,curated
+347,2008-02-20,2019-12-31,XK,Kosovo,curated
+609,1958-10-10,1975-11-13,EH,Spanish Sahara is today's Western Sahara territory,curated
+6511,1948-05-14,1967-06-09,PS,Gaza under Egyptian administration; territory of today's PS,curated
+6631,1948-05-14,1967-06-09,PS,West Bank under Jordanian administration; territory of today's PS,curated
+665,1920-04-26,1948-05-13,CSH665,Mandatory Palestine,curated
+3,1886-01-01,1959-01-02,CSH3,Territory of Alaska,curated
+4,1898-07-06,1959-08-20,CSH4,Territory of Hawaii,curated
+21,1886-01-01,1948-07-21,CSH21,Newfoundland,curated
+730,1886-01-01,1945-08-14,CSH730,Korea before partition,curated
diff --git a/inst/extdata/history_current_entities.csv b/inst/extdata/history_current_entities.csv
new file mode 100644
index 0000000..e4ecea8
--- /dev/null
+++ b/inst/extdata/history_current_entities.csv
@@ -0,0 +1,251 @@
+entity_key,name,geonameid,iso3166_1,iso3166_3,valid_from,valid_to,kind,note
+RW,Rwanda,49518,RW,,,,current,
+SO,Somalia,51537,SO,,,,current,
+YE,Yemen,69543,YE,,,,current,
+IQ,Iraq,99237,IQ,,,,current,
+SA,Saudi Arabia,102358,SA,,,,current,
+IR,Iran,130758,IR,,,,current,
+CY,Cyprus,146669,CY,,,,current,
+TZ,Tanzania,149590,TZ,,,,current,
+SY,Syria,163843,SY,,,,current,
+AM,Armenia,174982,AM,,,,current,
+KE,Kenya,192950,KE,,,,current,
+CD,Democratic Republic of the Congo,203312,CD,,,,current,
+DJ,Djibouti,223816,DJ,,,,current,
+UG,Uganda,226074,UG,,,,current,
+CF,Central African Republic,239880,CF,,,,current,
+SC,Seychelles,241170,SC,,,,current,
+JO,Jordan,248816,JO,,,,current,
+LB,Lebanon,272103,LB,,,,current,
+KW,Kuwait,285570,KW,,,,current,
+OM,Oman,286963,OM,,,,current,
+QA,Qatar,289688,QA,,,,current,
+BH,Bahrain,290291,BH,,,,current,
+AE,United Arab Emirates,290557,AE,,,,current,
+IL,Israel,294640,IL,,,,current,
+TR,Turkey,298795,TR,,,,current,
+ET,Ethiopia,337996,ET,,,,current,
+ER,Eritrea,338010,ER,,,,current,
+EG,Egypt,357994,EG,,,,current,
+SD,Sudan,366755,SD,,,,current,
+GR,Greece,390903,GR,,,,current,
+BI,Burundi,433561,BI,,,,current,
+EE,Estonia,453733,EE,,,,current,
+LV,Latvia,458258,LV,,,,current,
+AZ,Azerbaijan,587116,AZ,,,,current,
+LT,Lithuania,597427,LT,,,,current,
+SJ,Svalbard and Jan Mayen,607072,SJ,,,,current,
+GE,Georgia,614540,GE,,,,current,
+MD,Moldova,617790,MD,,,,current,
+BY,Belarus,630336,BY,,,,current,
+FI,Finland,660013,FI,,,,current,
+AX,Aland Islands,661882,AX,,,,current,
+UA,Ukraine,690791,UA,,,,current,
+MK,Macedonia,718075,MK,,,,current,
+HU,Hungary,719819,HU,,,,current,
+BG,Bulgaria,732800,BG,,,,current,
+AL,Albania,783754,AL,,,,current,
+PL,Poland,798544,PL,,,,current,
+RO,Romania,798549,RO,,,,current,
+XK,Kosovo,831053,XK,,,,current,
+ZW,Zimbabwe,878675,ZW,,,,current,
+ZM,Zambia,895949,ZM,,,,current,
+KM,Comoros,921929,KM,,,,current,
+MW,Malawi,927384,MW,,,,current,
+LS,Lesotho,932692,LS,,,,current,
+BW,Botswana,933860,BW,,,,current,
+MU,Mauritius,934292,MU,,,,current,
+SZ,Swaziland,934841,SZ,,,,current,
+RE,Reunion,935317,RE,,,,current,
+ZA,South Africa,953987,ZA,,,,current,
+YT,Mayotte,1024031,YT,,,,current,
+MZ,Mozambique,1036973,MZ,,,,current,
+MG,Madagascar,1062947,MG,,,,current,
+AF,Afghanistan,1149361,AF,,,,current,
+PK,Pakistan,1168579,PK,,,,current,
+BD,Bangladesh,1210997,BD,,,,current,
+TM,Turkmenistan,1218197,TM,,,,current,
+TJ,Tajikistan,1220409,TJ,,,,current,
+LK,Sri Lanka,1227603,LK,,,,current,
+BT,Bhutan,1252634,BT,,,,current,
+IN,India,1269750,IN,,,,current,
+MV,Maldives,1282028,MV,,,,current,
+IO,British Indian Ocean Territory,1282588,IO,,,,current,
+NP,Nepal,1282988,NP,,,,current,
+MM,Myanmar,1327865,MM,,,,current,
+UZ,Uzbekistan,1512440,UZ,,,,current,
+KZ,Kazakhstan,1522867,KZ,,,,current,
+KG,Kyrgyzstan,1527747,KG,,,,current,
+TF,French Southern Territories,1546748,TF,,,,current,
+HM,Heard Island and McDonald Islands,1547314,HM,,,,current,
+CC,Cocos Islands,1547376,CC,,,,current,
+PW,Palau,1559582,PW,,,,current,
+VN,Vietnam,1562822,VN,,,,current,
+TH,Thailand,1605651,TH,,,,current,
+ID,Indonesia,1643084,ID,,,,current,
+LA,Laos,1655842,LA,,,,current,
+TW,Taiwan,1668284,TW,,,,current,
+PH,Philippines,1694008,PH,,,,current,
+MY,Malaysia,1733045,MY,,,,current,
+CN,China,1814991,CN,,,,current,
+HK,Hong Kong,1819730,HK,,,,current,
+BN,Brunei,1820814,BN,,,,current,
+MO,Macao,1821275,MO,,,,current,
+KH,Cambodia,1831722,KH,,,,current,
+KR,South Korea,1835841,KR,,,,current,
+JP,Japan,1861060,JP,,,,current,
+KP,North Korea,1873107,KP,,,,current,
+SG,Singapore,1880251,SG,,,,current,
+CK,Cook Islands,1899402,CK,,,,current,
+TL,East Timor,1966436,TL,,,,current,
+RU,Russia,2017370,RU,,,,current,
+MN,Mongolia,2029969,MN,,,,current,
+AU,Australia,2077456,AU,,,,current,
+CX,Christmas Island,2078138,CX,,,,current,
+MH,Marshall Islands,2080185,MH,,,,current,
+FM,Micronesia,2081918,FM,,,,current,
+PG,Papua New Guinea,2088628,PG,,,,current,
+SB,Solomon Islands,2103350,SB,,,,current,
+TV,Tuvalu,2110297,TV,,,,current,
+NR,Nauru,2110425,NR,,,,current,
+VU,Vanuatu,2134431,VU,,,,current,
+NC,New Caledonia,2139685,NC,,,,current,
+NF,Norfolk Island,2155115,NF,,,,current,
+NZ,New Zealand,2186224,NZ,,,,current,
+FJ,Fiji,2205218,FJ,,,,current,
+LY,Libya,2215636,LY,,,,current,
+CM,Cameroon,2233387,CM,,,,current,
+SN,Senegal,2245662,SN,,,,current,
+CG,Republic of the Congo,2260494,CG,,,,current,
+PT,Portugal,2264397,PT,,,,current,
+LR,Liberia,2275384,LR,,,,current,
+CI,Ivory Coast,2287781,CI,,,,current,
+GH,Ghana,2300660,GH,,,,current,
+GQ,Equatorial Guinea,2309096,GQ,,,,current,
+NG,Nigeria,2328926,NG,,,,current,
+BF,Burkina Faso,2361809,BF,,,,current,
+TG,Togo,2363686,TG,,,,current,
+GW,Guinea-Bissau,2372248,GW,,,,current,
+MR,Mauritania,2378080,MR,,,,current,
+BJ,Benin,2395170,BJ,,,,current,
+GA,Gabon,2400553,GA,,,,current,
+SL,Sierra Leone,2403846,SL,,,,current,
+ST,Sao Tome and Principe,2410758,ST,,,,current,
+GI,Gibraltar,2411586,GI,,,,current,
+GM,Gambia,2413451,GM,,,,current,
+GN,Guinea,2420477,GN,,,,current,
+TD,Chad,2434508,TD,,,,current,
+NE,Niger,2440476,NE,,,,current,
+ML,Mali,2453866,ML,,,,current,
+EH,Western Sahara,2461445,EH,,,,current,
+TN,Tunisia,2464461,TN,,,,current,
+ES,Spain,2510769,ES,,,,current,
+MA,Morocco,2542007,MA,,,,current,
+MT,Malta,2562770,MT,,,,current,
+DZ,Algeria,2589581,DZ,,,,current,
+FO,Faroe Islands,2622320,FO,,,,current,
+DK,Denmark,2623032,DK,,,,current,
+IS,Iceland,2629691,IS,,,,current,
+GB,United Kingdom,2635167,GB,,,,current,
+CH,Switzerland,2658434,CH,,,,current,
+SE,Sweden,2661886,SE,,,,current,
+NL,Netherlands,2750405,NL,,,,current,
+AT,Austria,2782113,AT,,,,current,
+BE,Belgium,2802361,BE,,,,current,
+DE,Germany,2921044,DE,,,,current,
+LU,Luxembourg,2960313,LU,,,,current,
+IE,Ireland,2963597,IE,,,,current,
+MC,Monaco,2993457,MC,,,,current,
+FR,France,3017382,FR,,,,current,
+AD,Andorra,3041565,AD,,,,current,
+LI,Liechtenstein,3042058,LI,,,,current,
+JE,Jersey,3042142,JE,,,,current,
+IM,Isle of Man,3042225,IM,,,,current,
+GG,Guernsey,3042362,GG,,,,current,
+SK,Slovakia,3057568,SK,,,,current,
+CZ,Czech Republic,3077311,CZ,,,,current,
+NO,Norway,3144096,NO,,,,current,
+VA,Vatican,3164670,VA,,,,current,
+SM,San Marino,3168068,SM,,,,current,
+IT,Italy,3175395,IT,,,,current,
+SI,Slovenia,3190538,SI,,,,current,
+ME,Montenegro,3194884,ME,,,,current,
+HR,Croatia,3202326,HR,,,,current,
+BA,Bosnia and Herzegovina,3277605,BA,,,,current,
+AO,Angola,3351879,AO,,,,current,
+NA,Namibia,3355338,NA,,,,current,
+SH,Saint Helena,3370751,SH,,,,current,
+BV,Bouvet Island,3371123,BV,,,,current,
+BB,Barbados,3374084,BB,,,,current,
+CV,Cape Verde,3374766,CV,,,,current,
+GY,Guyana,3378535,GY,,,,current,
+GF,French Guiana,3381670,GF,,,,current,
+SR,Suriname,3382998,SR,,,,current,
+PM,Saint Pierre and Miquelon,3424932,PM,,,,current,
+GL,Greenland,3425505,GL,,,,current,
+PY,Paraguay,3437598,PY,,,,current,
+UY,Uruguay,3439705,UY,,,,current,
+BR,Brazil,3469034,BR,,,,current,
+FK,Falkland Islands,3474414,FK,,,,current,
+GS,South Georgia and the South Sandwich Islands,3474415,GS,,,,current,
+JM,Jamaica,3489940,JM,,,,current,
+DO,Dominican Republic,3508796,DO,,,,current,
+CU,Cuba,3562981,CU,,,,current,
+MQ,Martinique,3570311,MQ,,,,current,
+BS,Bahamas,3572887,BS,,,,current,
+BM,Bermuda,3573345,BM,,,,current,
+AI,Anguilla,3573511,AI,,,,current,
+TT,Trinidad and Tobago,3573591,TT,,,,current,
+KN,Saint Kitts and Nevis,3575174,KN,,,,current,
+DM,Dominica,3575830,DM,,,,current,
+AG,Antigua and Barbuda,3576396,AG,,,,current,
+LC,Saint Lucia,3576468,LC,,,,current,
+TC,Turks and Caicos Islands,3576916,TC,,,,current,
+AW,Aruba,3577279,AW,,,,current,
+VG,British Virgin Islands,3577718,VG,,,,current,
+VC,Saint Vincent and the Grenadines,3577815,VC,,,,current,
+MS,Montserrat,3578097,MS,,,,current,
+MF,Saint Martin,3578421,MF,,,,current,
+BL,Saint Barthelemy,3578476,BL,,,,current,
+GP,Guadeloupe,3579143,GP,,,,current,
+GD,Grenada,3580239,GD,,,,current,
+KY,Cayman Islands,3580718,KY,,,,current,
+BZ,Belize,3582678,BZ,,,,current,
+SV,El Salvador,3585968,SV,,,,current,
+GT,Guatemala,3595528,GT,,,,current,
+HN,Honduras,3608932,HN,,,,current,
+NI,Nicaragua,3617476,NI,,,,current,
+CR,Costa Rica,3624060,CR,,,,current,
+VE,Venezuela,3625428,VE,,,,current,
+EC,Ecuador,3658394,EC,,,,current,
+CO,Colombia,3686110,CO,,,,current,
+PA,Panama,3703430,PA,,,,current,
+HT,Haiti,3723988,HT,,,,current,
+AR,Argentina,3865483,AR,,,,current,
+CL,Chile,3895114,CL,,,,current,
+BO,Bolivia,3923057,BO,,,,current,
+PE,Peru,3932488,PE,,,,current,
+MX,Mexico,3996063,MX,,,,current,
+PF,French Polynesia,4030656,PF,,,,current,
+PN,Pitcairn,4030699,PN,,,,current,
+KI,Kiribati,4030945,KI,,,,current,
+TK,Tokelau,4031074,TK,,,,current,
+TO,Tonga,4032283,TO,,,,current,
+WF,Wallis and Futuna,4034749,WF,,,,current,
+WS,Samoa,4034894,WS,,,,current,
+NU,Niue,4036232,NU,,,,current,
+MP,Northern Mariana Islands,4041468,MP,,,,current,
+GU,Guam,4043988,GU,,,,current,
+PR,Puerto Rico,4566966,PR,,,,current,
+VI,U.S. Virgin Islands,4796775,VI,,,,current,
+UM,United States Minor Outlying Islands,5854968,UM,,,,current,
+AS,American Samoa,5880801,AS,,,,current,
+CA,Canada,6251999,CA,,,,current,
+US,United States,6252001,US,,,,current,
+PS,Palestinian Territory,6254930,PS,,,,current,
+RS,Serbia,6290252,RS,,,,current,
+AQ,Antarctica,6697173,AQ,,,,current,
+SX,Sint Maarten,7609695,SX,,,,current,
+CW,Curacao,7626836,CW,,,,current,
+BQ,"Bonaire, Saint Eustatius and Saba",7626844,BQ,,,,current,
+SS,South Sudan,7909807,SS,,,,current,
diff --git a/inst/extdata/history_geonames_names.csv b/inst/extdata/history_geonames_names.csv
new file mode 100644
index 0000000..43045f6
--- /dev/null
+++ b/inst/extdata/history_geonames_names.csv
@@ -0,0 +1,250 @@
+geonameid,name
+8505032,Netherlands Antilles
+8505032,Antia Hulandes
+8505032,Antias Hulandes
+8505032,Antilhas Neerlandesas
+8505032,Antillas Holandesas
+8505032,Antille Olandesi
+8505032,Antilles Neerlandaises
+8505032,Antilles Néerlandaises
+8505032,De nederlandske antiller
+8505032,Dutch Antilles
+8505032,Nederlandsch West-Indie
+8505032,Nederlandsch West-Indië
+8505032,Nederlandse Antillen
+8505032,Niderlands'ki Antil's'ki ostrovi
+8505032,Niderlandskie Antil'skie ostrova
+8505032,Niederlaendische Antillen
+8505032,Niederländische Antillen
+8505032,alantyl alhwlndyt
+8505032,he shu an de lie si
+8505032,nedeollandeulyeong antilleseu
+8505032,oranda lingantiru
+8505032,Нидерландские Антильские острова
+8505032,Нідерландські Антильські острови
+8505032,الأنتيل الهولندية
+8505032,オランダ領アンティル
+8505032,荷属安的列斯
+8505032,荷屬安地列斯
+8505032,네덜란드령 안틸레스
+8505031,Czechoslovakia
+8505031,An t-Seic-Slobhac
+8505031,An t-Seic-Slòbhac
+8505031,An tSeicslovaic
+8505031,An tSeicslóvaic
+8505031,CHSSR
+8505031,CS
+8505031,CSK
+8505031,Cechoslovacia
+8505031,Cecoslofacia
+8505031,Cecoslovacchia
+8505031,Cecoslovachia
+8505031,Cecoslovachie
+8505031,Cecusluvachia
+8505031,Cehoslovacia
+8505031,Cehoslovacka
+8505031,Cehoslovakii
+8505031,Cehoslovakija
+8505031,Cehoslovakio
+8505031,Cekosllovakia
+8505031,Cekoslovakija
+8505031,Cekoslovakya
+8505031,Cekoslowakia
+8505031,Cekoslowakya
+8505031,Cesko-Slovensko
+8505031,Ceskoslovaska
+8505031,Ceskoslovensko
+8505031,Ceskoslowakska
+8505031,Cexoslovakiya
+8505031,Checoslovachia
+8505031,Checoslovaquia
+8505031,Checoslováquia
+8505031,Chehkhaslavakija
+8505031,Chekhoslovachchina
+8505031,Chekhoslovachka
+8505031,Chekhoslovaki
+8505031,Chekhoslovakija
+8505031,Chekoslovakia
+8505031,Chexoslovakiya
+8505031,Chikusluwakya
+8505031,Csehszlovakia
+8505031,Csehszlovákia
+8505031,Cssr
+8505031,Czechoslovakie
+8505031,Czechoslowacja
+8505031,Czechosłowacja
+8505031,Cékoslowakia
+8505031,Tchecoslovakia
+8505031,Tchecoslovakie
+8505031,Tchecoslovaquie
+8505031,Tchekoslovakia
+8505031,Tch·ècoslovaquie
+8505031,Tchécoslovakie
+8505031,Tchécoslovaquie
+8505031,Tekkoslovakia
+8505031,Tiep Khac
+8505031,Tiệp Khắc
+8505031,Tjeckoslovakien
+8505031,Tjekkiet
+8505031,Tschechoslowakaei
+8505031,Tschechoslowakei
+8505031,Tschechoslowakäi
+8505031,Tsechoslovakia
+8505031,Tsehhoslovakkia
+8505031,Tsekkoslovakia
+8505031,Tsekoslobakya
+8505031,Tsiecoslofacia
+8505031,Tsjecho-Slowakije
+8505031,Tsjechoslowakije
+8505031,Tsjeggo-Slowakye
+8505031,Tsjekkoslovakia
+8505031,Txecoslovaquia
+8505031,Txecoslovàquia
+8505031,Txekoslovakia
+8505031,Tzecoslovachia
+8505031,Tzecoslovàchia
+8505031,Tékkóslóvakía
+8505031,Tšehhoslovakkia
+8505031,Tšekkoslovakia
+8505031,caikosalavaki'a
+8505031,cekkeasleavakya
+8505031,cekkocilovakkiya
+8505031,cekoslobhakiya
+8505031,cekoslovakiya
+8505031,cekoslovekiya
+8505031,cekoslovhakiya
+8505031,chekoseullobakia
+8505031,chekosurobakia
+8505031,chkslwaky
+8505031,jie ke si luo fa ke
+8505031,pra thes che kos lo wa keiy
+8505031,tshykwslwfakya
+8505031,zkwslwbqyh
+8505031,Çekosllovakia
+8505031,Çekoslovakya
+8505031,Çekoslowakya
+8505031,Çexoslovakiya
+8505031,Ĉeĥoslovakio
+8505031,Čehoslovakii
+8505031,Čehoslovačka
+8505031,Čehoslovākija
+8505031,Čekoslovakija
+8505031,Česko-Slovensko
+8505031,Československo
+8505031,Českosłowakska
+8505031,Češkoslovaška
+8505031,Čěskosłowakska
+8505031,Τσεχοσλοβακία
+8505031,ЧССР
+8505031,Чехословаки
+8505031,Чехословакия
+8505031,Чехословачка
+8505031,Чехословаччина
+8505031,Чэхаславакія
+8505031,Չեխոսլովակիա
+8505031,טשעכאסלאוואקיי
+8505031,צכוסלובקיה
+8505031,تشيكوسلوفاكيا
+8505031,چکسلواکی
+8505031,چیکوسلواکیہ
+8505031,چیکوسلوواکیہ
+8505031,چێکۆسلۆڤاکیا
+8505031,चेकोस्लोभाकिया
+8505031,चेकोस्लोवाकिया
+8505031,चेकोस्लोव्हाकिया
+8505031,চেকোস্লোভাকিয়া
+8505031,ਚੈਕੋਸਲਵਾਕੀਆ
+8505031,செக்கோசிலோவாக்கியா
+8505031,ಚೆಕೊಸ್ಲೊವೇಕಿಯಾ
+8505031,ചെക്കൊസ്ലൊവാക്യ
+8505031,චෙකොස්ලෝවැකියාව
+8505031,ประเทศเชโกสโลวาเกีย
+8505031,ချက်ကိုဆလိုဗားကီးယားနိုင်ငံ
+8505031,ჩეხოსლოვაკია
+8505031,チェコスロバキア
+8505031,捷克斯洛伐克
+8505031,체코슬로바키아
+8505033,Serbia and Montenegro
+8505033,Federal Republic of Yugoslavia
+8505033,Bundesrepublik Jugoslawien
+8505033,CS
+8505033,Crbija i Crna Gora
+8505033,Cрбија и Црна Гора
+8505033,SCG
+8505033,Savezna Republika Jugoslavija
+8505033,Serbia e Montenegro
+8505033,Serbia og Montenegro
+8505033,Serbia y Montenegro
+8505033,Serbie-et-Montenegro
+8505033,Serbie-et-Monténégro
+8505033,Serbien und Montenegro
+8505033,Serbien-Montenegro
+8505033,Serbija i Chernogorija
+8505033,Servia e Montenegro
+8505033,Srbija i Crna Gora
+8505033,State Union of Serbia and Montenegro
+8505033,Sérvia e Montenegro
+8505033,seleubia montenegeulo
+8505033,serubia・monteneguro
+8505033,srbya waljbl alaswd
+8505033,Савезна Република Југославија
+8505033,Сербия и Черногория
+8505033,صربيا والجبل الأسود
+8505033,セルビア・モンテネグロ
+8505033,세르비아 몬테네그로
+8354410,German Democratic Republic
+8354410,Allemagne de l'Est
+8354410,DDR
+8354410,Deutsche Demokratische Republik
+8354410,East Germany
+8354410,GDR
+8354410,Germanskaja Demokraticheskaja Respublika
+8354410,Istocna Njemacka
+8354410,Istočna Njemačka
+8354410,NRD
+8354410,Niemiecka Republika Demokratyczna
+8354410,Njemacka Demokratska Republika
+8354410,Njemačka Demokratska Republika
+8354410,RDA
+8354410,Repubblica Democratica Tedesca
+8354410,Republique democratique allemande
+8354410,République démocratique allemande
+8354410,SBZ
+8354410,Sowjetische Besatzungszone
+8354410,ГДР
+8354410,Германская Демократическая Республика
+11612757,Ruanda-Urundi
+11608491,Republic of Vietnam
+11608491,South Vietnam
+8505034,"Yemen, Democratic"
+8505034,Democratic Yemen
+8505034,Jumhuriyat Al-Yaman Al-Dimuqratiyah Al-Sha'biyah
+8505034,Jumhūrīyat Al-Yaman Al-Dīmuqrāṭīyah Al-Sha'bīyah
+8505034,People's Democratic Republic of Yemen
+8505034,South Yemen
+8505034,YD
+8505034,YMD
+8505034,Yemen (Aden)
+8505034,Yemen  Democratic
+8505034,jmhwryt alyaman aldymuqratyt alshaʿbit
+8505034,جمهورية اليَمَنْ الديمُقراطية الشَعْبِيّة
+8354411,Union of Soviet Socialist Republics
+8354411,Neuvostoliitto
+8354411,SSSR
+8354411,Sojuz Sovetskikh Socialisticheskikh Respublik
+8354411,Sovetskij Sojuz
+8354411,Sovetskiy Soyuz
+8354411,Soviet Union
+8354411,Sovjet-Unie
+8354411,Sowietunion
+8354411,Soyuz Sovetskikh Sotsialisticheskikh Respublik
+8354411,URSS
+8354411,USSR
+8354411,UdSSR
+8354411,Union des republiques socialistes sovietiques
+8354411,Union des républiques socialistes soviétiques
+8354411,Union sovietique
+8354411,Union soviétique
+8354411,СССР
+8354411,Советский Союз
+8354411,Союз Советских Социалистических Республик
diff --git a/man/GNRS_local.Rd b/man/GNRS_local.Rd
index 08c36c4..20c4912 100644
--- a/man/GNRS_local.Rd
+++ b/man/GNRS_local.Rd
@@ -10,7 +10,9 @@ GNRS_local(
   alternate_names = TRUE,
   dir = gnrs_cache_dir(),
   build_missing = interactive(),
-  quiet = FALSE
+  quiet = FALSE,
+  history = c("all", "current", "at_date"),
+  tolerance_years = 1
 )
 }
 \arguments{
@@ -38,12 +40,48 @@ downloaded silently: the function reports what is missing and the call that
 would fix it.  Set it to TRUE to allow an unattended build.}
 
 \item{quiet}{Suppress progress messages?}
+
+\item{history}{Historical political divisions: \code{"all"} (the default;
+also matches former countries such as the USSR, Yugoslavia or
+Czechoslovakia, flagging such matches, so a record named with a political
+division that was ever accurate resolves), \code{"current"} (today's
+divisions only, as the web service does), or \code{"at_date"} (as "all",
+but a former country is accepted only if it existed at the record's date,
+taken from an optional \code{date} column of years or ISO dates; a name
+marked as former, such as "Former USSR", is accepted for any later date,
+and a state or county that resolves within a successor is kept and flagged
+whatever the date).  Needs the \code{"history"} component, built from
+tables shipped with the package plus the CShapes historical boundaries,
+which are read from the \code{cshapes} package when it is installed and
+otherwise downloaded from the publisher (about 60 MB) when
+\code{build_missing} allows building; with \code{history = "current"}
+nothing beyond the ordinary components is needed.  When the component
+cannot be prepared (a package not installed, a download declined), the
+call says so and resolves current divisions only.}
+
+\item{tolerance_years}{With \code{history = "at_date"}, how many years
+either side of a former country's existence a record date may fall.  A
+single non-negative number.}
 }
 \value{
 A data.frame with the same columns as \code{GNRS()}, one row per
-  input row in input order.  Scores are numeric rather than the character
-  strings the web service returns; identifiers are character, as the web
-  service returns them; empty values are "".
+  input row in input order.  With \code{history} other than "current",
+  further columns: \code{entity_key}, \code{is_historical},
+  \code{entity_valid_from}, \code{entity_valid_to}, \code{successors} (the
+  current countries descending from a matched former country),
+  \code{subnational_resolved_in} and \code{subnational_status} (a state or
+  county given under a former country is looked up within its successors;
+  "unverifiable" if none contains it), and \code{date_check}.  Whatever
+  \code{history} is, four further columns report a state or county that is
+  an alternative or superseded division rather than one the service knows
+  (a Swedish landskap, a Watsonian vice-county, a Norwegian county from
+  before the 2020 reform): \code{alt_division} (its name),
+  \code{alt_division_system}, \code{alt_division_level} and
+  \code{alt_division_extent_known} (whether the GADM units it covers are
+  recorded, so that a coordinate could be checked against it); "" or NA
+  for a row that resolved ordinarily.  Scores are numeric rather than the
+  character strings the web service returns; identifiers are character, as
+  the web service returns them; empty values are "".
 }
 \description{
 Resolves country, state/province and county/parish names against a locally
diff --git a/man/GNRS_local_build.Rd b/man/GNRS_local_build.Rd
index 11a174f..20e2d9c 100644
--- a/man/GNRS_local_build.Rd
+++ b/man/GNRS_local_build.Rd
@@ -15,8 +15,16 @@ GNRS_local_build(
 }
 \arguments{
 \item{sources}{Character vector of components to build: \code{"gnrs"},
-\code{"geonames"} (the two defaults), \code{"points"} and
-\code{"gadm"}.  The other components are layered on or filtered to the
+\code{"geonames"} (the two defaults), \code{"points"}, \code{"gadm"},
+and, for \code{GNRS_local()}'s historical modes, \code{"cshapes"} (the
+CShapes 2.0 boundaries of former countries, from the \code{cshapes}
+package when it is installed, otherwise a 60 MB download) and
+\code{"altdiv"} (alternative and superseded sub-national divisions, from
+curation shipped with the package: nothing is downloaded, and
+\code{GNRS_local()} builds it on first use) and
+\code{"history"} (the historical entities, names and lineage, assembled
+from tables shipped with the package and from CShapes, which it builds if
+it is missing).  The other components are layered on or filtered to the
 service's tables, so \code{"gnrs"} is built first if it is missing
 whatever is asked for.}
 
@@ -44,7 +52,7 @@ is kept in the standard user cache directory, and can be removed again with
 \code{GNRS_local_remove()}.
 }
 \details{
-Two components are fetched by default, and two more can be added.
+Two components are fetched by default, and five more can be added.
 \code{"gnrs"} is the web service's own
 reference tables of countries, states/provinces and counties/parishes,
 fetched through its API in a few small requests: every political division it
@@ -87,6 +95,17 @@ A link whose names agree outright is kept whatever the point says, since
 GeoNames places its points near an edge often enough.  Build it before
 \code{"gadm"} (the order is arranged whatever order is given).
 
+\code{"cshapes"} and \code{"history"} serve the historical modes of
+\code{GNRS_local()}.  The first is CShapes 2.0, the boundaries of every
+independent state and dependency from 1886 to 2019, read from the
+\code{cshapes} package when it is installed and otherwise downloaded from
+its publisher (about 60 MB; CC BY-NC-SA 4.0, so nothing derived from it
+ships with the package).  The second assembles the historical entities,
+their names, codes and lineage from tables shipped with the package and
+from CShapes, and prunes its names against the current name table, so it
+is built last and rebuilt whenever a component it draws on is rebuilt.
+Asking for \code{"history"} builds \code{"cshapes"} if it is missing.
+
 Each component is recorded with its version, so that results obtained locally
 can be cited as precisely as results from the web service.  Use
 \code{GNRS_local_status()} to see what has been built.
diff --git a/man/GNRS_local_remove.Rd b/man/GNRS_local_remove.Rd
index 73332e0..d59de45 100644
--- a/man/GNRS_local_remove.Rd
+++ b/man/GNRS_local_remove.Rd
@@ -12,7 +12,9 @@ GNRS_local_remove(dir = gnrs_cache_dir(), sources = NULL, ask = interactive())
 \item{sources}{NULL, the default, removes everything.  Otherwise the
 components to remove, for instance \code{"gadm"} to go back to resolving
 against the service's own GADM identifiers; the reference tables are
-rederived from what remains.}
+rederived from what remains, and a built \code{"history"} component is
+rebuilt against them, or removed along with \code{"cshapes"}, which it
+is derived from.}
 
 \item{ask}{Ask for confirmation before deleting? Defaults to TRUE in an
 interactive session.}
diff --git a/tests/testthat/helper-local.R b/tests/testthat/helper-local.R
index 2e00f11..b65a5c1 100644
--- a/tests/testthat/helper-local.R
+++ b/tests/testthat/helper-local.R
@@ -153,3 +153,21 @@ gnrs_test_resolve <- function(dir, country, state = "", county = "", ...) {
   )
   GNRS_local(df, dir = dir, build_missing = FALSE, quiet = TRUE, ...)
 }
+
+# CShapes for tests that need the history component. Nothing derived from CShapes ships
+# with the package (CC BY-NC-SA 4.0; the package is MIT), so the history component is
+# assembled from the user's own CShapes. For tests that copy is built ONCE per session
+# from the cshapes package (no download) and copied into each test cache; a test that
+# needs it skips where cshapes, countrycode or sf is not installed.
+gnrs_test_cshapes <- function(dir) {
+  testthat::skip_if_not_installed("cshapes")
+  testthat::skip_if_not_installed("countrycode")
+  testthat::skip_if_not_installed("sf")
+  src <- file.path(tempdir(), "gnrs-test-cshapes")
+  if (!file.exists(gnrs_cshapes_versions_path(src))) {
+    dir.create(src, recursive = TRUE, showWarnings = FALSE)
+    gnrs_build_cshapes(dir = src, quiet = TRUE)
+  }
+  file.copy(list.files(src, pattern = "^cshapes-", full.names = TRUE), dir, overwrite = TRUE)
+  invisible(dir)
+}
diff --git a/tests/testthat/test-local-altdiv.R b/tests/testthat/test-local-altdiv.R
new file mode 100644
index 0000000..a0a4520
--- /dev/null
+++ b/tests/testthat/test-local-altdiv.R
@@ -0,0 +1,88 @@
+context("alternative and superseded sub-national divisions")
+
+# Built from curation shipped with the package; nothing is downloaded and nothing is
+# derived from another component, so this needs no backbone.
+
+dir <- file.path(tempdir(), "gnrs-altdiv-cache")
+unlink(dir, recursive = TRUE)
+dir.create(dir, recursive = TRUE, showWarnings = FALSE)
+gnrs_build_altdiv(dir = dir, quiet = TRUE)
+
+test_that("the component builds and reports what it knows", {
+  expect_true(gnrs_is_built("altdiv", dir))
+  a <- gnrs_altdiv(dir)
+  expect_true(all(c("units", "names", "extent") %in% names(a)))
+  expect_false(anyDuplicated(a$units$entity_key) > 0)
+  expect_true(all(a$extent$entity_key %in% a$units$entity_key))
+  expect_true(all(a$names$entity_key %in% a$units$entity_key))
+  # a unit has an extent exactly when its key appears in the extent table
+  expect_equal(sort(a$units$entity_key[a$units$extent_known]), sort(unique(a$extent$entity_key)))
+})
+
+test_that("a division that IS a GADM unit is not diverted to another system", {
+  # nothing here belongs to another division system, and no alias is registered for
+  # these countries: Norwegian counties are covered only where a reform superseded them
+  m <- gnrs_altdiv_match(c("NO", "US", "GB"), c("Akershus", "California", "Greater London"), dir = dir)
+  expect_true(all(is.na(m$entity_key)))
+  # a bare lan name IS registered, as an alias of that same lan: the GNRS reference
+  # names these units inconsistently ("Norrbotten" but "Vastmanlands lan"), so the bare
+  # name has to be recognised. It carries the lan's own extent, and the resolver takes
+  # an exact GADM match first in any case.
+  m <- gnrs_altdiv_match("SE", "Stockholm", dir = dir)
+  expect_equal(m$kind, "alias")
+  expect_true(m$extent_known)
+  expect_equal(gnrs_altdiv_extent(m$entity_key, dir), "SWE.15_1")
+})
+
+test_that("parallel systems are recognised but carry no extent yet", {
+  m <- gnrs_altdiv_match(c("SE", "SE", "SE"), c("Uppland", "Småland", "Lule lappmark"), dir = dir)
+  expect_equal(m$system, c("se-landskap", "se-landskap", "se-lappmark"))
+  expect_equal(m$kind, rep("parallel", 3))
+  expect_false(any(m$extent_known))
+  expect_equal(gnrs_altdiv_extent(m$entity_key[1], dir), character(0))
+})
+
+test_that("vice-counties are matched by the way records write them", {
+  m <- gnrs_altdiv_match(rep("GB", 3), c("VC57 Derbyshire", "VC1 West Cornwall", "VC 9 Dorset"), dir = dir)
+  expect_equal(unique(m$system), "gb-vice-county")
+  # a county that is not a vice-county is left alone
+  expect_true(is.na(gnrs_altdiv_match("GB", "Greater London", dir = dir)$entity_key))
+})
+
+test_that("a lan under the name records use resolves to that same lan", {
+  m <- gnrs_altdiv_match(c("SE", "SE"), c("Norrbottens län", "Norrbotten län"), dir = dir)
+  expect_equal(m$kind, c("alias", "alias"))
+  expect_true(all(m$extent_known))
+  expect_equal(gnrs_altdiv_extent(m$entity_key[1], dir), "SWE.10_1")
+})
+
+test_that("superseded counties carry their extent and their period", {
+  m <- gnrs_altdiv_match(rep("NO", 3), rep("Viken", 3),
+                         dates = c("2021-06-01", "2025-06-01", NA), dir = dir)
+  expect_equal(unique(m$entity_key), "NO-VIKEN")
+  expect_true(all(m$extent_known))
+  expect_setequal(gnrs_altdiv_extent("NO-VIKEN", dir), c("NOR.1_1", "NOR.4_1", "NOR.2_1"))
+  # Viken existed 2020-01-01 to 2023-12-31; with no date there is nothing to check
+  expect_equal(m$in_period, c(TRUE, FALSE, NA))
+  # Innlandet was not dissolved in 2024
+  expect_true(gnrs_altdiv_match("NO", "Innlandet", dates = "2025-06-01", dir = dir)$in_period)
+})
+
+test_that("extents name GADM units that exist", {
+  a <- gnrs_altdiv(dir)
+  expect_true(all(grepl("^[A-Z]{3}[.][0-9]+(_[0-9]+)?$", a$extent$gid)))
+  expect_true(all(a$extent$level %in% c(1L, 2L)))
+})
+
+test_that("the session cache is for one directory, and the build creates the directory", {
+  a <- file.path(tempdir(), "gnrs-altdiv-a", "nested")
+  b <- file.path(tempdir(), "gnrs-altdiv-b")
+  unlink(c(dirname(a), b), recursive = TRUE)
+  expect_false(dir.exists(a))
+  gnrs_build_altdiv(dir = a, quiet = TRUE)
+  expect_true(gnrs_is_built("altdiv", a))
+  expect_false(is.null(gnrs_altdiv(a)))
+  # a directory without the component gets nothing, not a's tables
+  expect_null(gnrs_altdiv(b))
+  expect_false(is.null(gnrs_altdiv(a)))
+})
diff --git a/tests/testthat/test-local-build.R b/tests/testthat/test-local-build.R
index cf17039..31a0c45 100644
--- a/tests/testthat/test-local-build.R
+++ b/tests/testthat/test-local-build.R
@@ -94,3 +94,11 @@ test_that("reading the alternate names keeps only what the SQL keeps", {
   expect_equal(alt$name, c("Estados Unidos", "United States"))
   expect_equal(alt$geonameid, c(6252001L, 6252001L))
 })
+
+test_that("a standalone component builds without the service's tables", {
+  fresh <- file.path(tempdir(), "gnrs-standalone")
+  unlink(fresh, recursive = TRUE)
+  expect_silent(GNRS_local_build("altdiv", dir = fresh, quiet = TRUE))
+  expect_true(gnrs_is_built("altdiv", fresh))
+  expect_false(gnrs_is_built("gnrs", fresh))
+})
diff --git a/tests/testthat/test-local-gadm.R b/tests/testthat/test-local-gadm.R
index aa90ddb..9ae9a78 100644
--- a/tests/testthat/test-local-gadm.R
+++ b/tests/testthat/test-local-gadm.R
@@ -114,6 +114,7 @@ test_that("GADM divisions link by identifier, HASC and name, and the rest are ad
 
 test_that("a built layer changes what GNRS_local() reports, and can be removed again", {
   dir <- gnrs_test_backbone()
+  gnrs_test_cshapes(dir)   # GNRS_local() defaults to history = "all"
   nanoparquet::write_parquet(gnrs_test_gadm(), gnrs_gadm_path(dir), compression = "gzip")
   saveRDS(list(source = "gadm", version = "test", downloaded = "2024-06-01"), gnrs_provenance_path("gadm", dir))
   gnrs_finalize_reference(dir, quiet = TRUE)
diff --git a/tests/testthat/test-local-history.R b/tests/testthat/test-local-history.R
new file mode 100644
index 0000000..e8b5909
--- /dev/null
+++ b/tests/testthat/test-local-history.R
@@ -0,0 +1,189 @@
+context("offline resolution of historical political divisions")
+
+# Against the synthetic reference in helper-local.R plus the history component.
+# Nothing derived from CShapes ships (CC BY-NC-SA 4.0; the package is MIT), so the
+# history component is assembled from the shipped curation and a CShapes copy built
+# into the test cache from the cshapes package - no download, but the package is needed.
+
+dir <- gnrs_test_backbone()
+gnrs_test_cshapes(dir)
+gnrs_build_history(dir = dir, quiet = TRUE)
+
+test_that("nothing derived from CShapes ships with the package", {
+  # the history component's own files; other components ship theirs alongside
+  shipped <- list.files(dirname(gnrs_extdata("history_codes.csv")), pattern = "^history_.*[.]csv$")
+  expect_true(file.exists(file.path(dirname(gnrs_extdata("history_codes.csv")), "SOURCES.md")))
+  expect_setequal(shipped, c("history_codes.csv", "history_current_entities.csv",
+                             "history_curated_entities.csv", "history_curated_lineage.csv",
+                             "history_curated_names.csv", "history_curated_periods.csv",
+                             "history_geonames_names.csv"))
+  # the tables that were CShapes-derived must not come back
+  expect_false(any(c("cshapes_entity_periods.csv", "history_entities.csv",
+                     "history_lineage.csv", "history_names.csv") %in% shipped))
+  # the only CSH<gwcode> entities in the curation are the ones named by hand
+  ent <- utils::read.csv(gnrs_extdata("history_curated_entities.csv"), na.strings = "")
+  expect_setequal(grep("^CSH[0-9]+$", ent$entity_key, value = TRUE),
+                  c("CSH665", "CSH3", "CSH4", "CSH21", "CSH730"))
+})
+
+test_that("assembly at build time reproduces the tables that used to ship", {
+  # counts of the inst/extdata tables written by data-raw/history_crosswalk.R before
+  # 2026-09-22, which the assembly was checked against row for row
+  h <- gnrs_history(dir)
+  expect_equal(nrow(h$entities), 326L)
+  expect_equal(nrow(h$lineage), 125L)
+  expect_equal(nrow(h$periods), 255L)
+  expect_equal(sum(h$entities$kind == "historical" & grepl("^CSH[0-9]+$", h$entities$entity_key)), 60L)
+  expect_true(any(grepl("^CShapes geometry overlap", h$lineage$source)))
+})
+
+test_that("record dates parse from years, ISO dates and Dates", {
+  d <- gnrs_parse_record_date(c(1985, 1970))
+  expect_equal(d, as.Date(c("1985-07-01", "1970-07-01")))
+  # a vector with no ISO dates must not fail: paste0(character(0), "-01") is "-01"
+  expect_silent(gnrs_parse_record_date(c("1985", NA)))
+  expect_equal(gnrs_parse_record_date(c("1991-12", "2005-03-04", "not a date")),
+               as.Date(c("1991-12-01", "2005-03-04", NA)))
+  expect_equal(gnrs_parse_record_date(as.Date("2001-01-01")), as.Date("2001-01-01"))
+})
+
+test_that("the history component gives every entity a unique identifier", {
+  h <- gnrs_history(dir)
+  expect_false(anyDuplicated(h$entities$entity_id) > 0)
+  synthetic <- is.na(h$entities$geonameid)
+  expect_true(all(h$entities$entity_id[synthetic] > gnrs_history_synthetic_base()))
+  expect_equal(h$entities$entity_id[h$entities$entity_key == "SUHH"], 8354411L)
+  # "NA" is Namibia's code, not a missing value
+  expect_true("NA" %in% h$entities$entity_key)
+  expect_false(anyNA(h$entities$entity_key))
+  expect_true(all(c("entities", "names", "lineage", "periods", "codes", "collisions") %in%
+    sub("^history-(.*)\\.gz\\.parquet$", "\\1", list.files(dir, pattern = "^history-"))))
+})
+
+test_that("history = 'current' resolves against today's divisions only; 'all' is the default", {
+  cur <- gnrs_test_resolve(dir, c("United States", "USSR"), c("Arizona", ""), history = "current")
+  expect_equal(cur$country, c("United States", ""))
+  expect_false("entity_key" %in% names(cur))
+  def <- gnrs_test_resolve(dir, c("United States", "USSR"), c("Arizona", ""))
+  all <- gnrs_test_resolve(dir, c("United States", "USSR"), c("Arizona", ""), history = "all")
+  expect_identical(def, all)
+  expect_equal(def$entity_key, c("US", "SUHH"))
+  # the web-service columns agree with "current" wherever no former country is involved
+  expect_identical(def[1, names(cur)], cur[1, ])
+})
+
+test_that("former countries resolve with history = 'all'", {
+  r <- gnrs_test_resolve(dir, c("USSR", "Yugoslavia", "Czechoslovakia (former)", "United States"),
+                         history = "all")
+  expect_equal(r$entity_key, c("SUHH", "YUCS", "CSHH", "US"))
+  expect_equal(r$is_historical, c(TRUE, TRUE, TRUE, FALSE))
+  expect_match(r$successors[1], "(^|;)RU(;|$)")
+  expect_match(r$successors[1], "(^|;)LT(;|$)")
+  # the lineage is followed through Serbia to Kosovo, which seceded from it
+  expect_match(r$successors[2], "(^|;)RS(;|$)")
+  expect_match(r$successors[2], "(^|;)XK(;|$)")
+  expect_equal(r$successors[4], "")
+  # "Czechoslovakia (former)" is not an exact alternate name (case differs): fuzzy
+  expect_match(r$match_method_country[3], "^fuzzy")
+})
+
+test_that("names of synthetic CShapes entities match exactly only", {
+  r <- gnrs_test_resolve(dir, c("Northeastern Rhodesia", "Northeastern Rhodesie"), history = "all")
+  expect_equal(r$entity_key[1], "CSH5518")
+  expect_false(identical(r$entity_key[2], "CSH5518"))
+})
+
+test_that("history = 'at_date' keeps a former country only while it existed", {
+  df <- data.frame(user_id = 1:3, country = "USSR", state_province = "", county_parish = "",
+                   date = c(1985, 1992, 2005), stringsAsFactors = FALSE)
+  r <- GNRS_local(df, dir = dir, build_missing = FALSE, quiet = TRUE, history = "at_date")
+  # 1992 is within the default one-year tolerance of 1991-12-25
+  expect_equal(r$entity_key, c("SUHH", "SUHH", ""))
+  expect_match(r$date_check[1], "valid at record date")
+  expect_match(r$date_check[3], "outside its validity")
+  r0 <- GNRS_local(df, dir = dir, build_missing = FALSE, quiet = TRUE, history = "at_date",
+                   tolerance_years = 0)
+  expect_equal(r0$entity_key, c("SUHH", "", ""))
+})
+
+test_that("a name marked as former is accepted after the division ended, not before it began", {
+  expect_equal(gnrs_is_former_label(c("Former USSR", "EX-USSR", "Ex USSR", "USSR (former)",
+                                      "Yugoslavia (Former)", "ehemalige DDR", "USSR", "Exeter", "Texas")),
+               c(TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, FALSE, FALSE, FALSE))
+  df <- data.frame(user_id = 1:3, country = c("Former USSR", "Ex-USSR", "Former USSR"),
+                   state_province = "", county_parish = "", date = c(1995, 2010, 1900),
+                   stringsAsFactors = FALSE)
+  r <- GNRS_local(df, dir = dir, build_missing = FALSE, quiet = TRUE, history = "at_date")
+  expect_equal(r$entity_key, c("SUHH", "SUHH", ""))
+  expect_match(r$date_check[1], "named as former")
+  expect_match(r$date_check[3], "outside its validity")
+})
+
+test_that("tolerance_years must be a single non-negative number", {
+  df <- data.frame(user_id = 1, country = "USSR", state_province = "", county_parish = "", date = "1970")
+  expect_error(GNRS_local(df, dir = dir, history = "at_date", tolerance_years = NA, quiet = TRUE), "tolerance_years")
+  expect_error(GNRS_local(df, dir = dir, history = "at_date", tolerance_years = c(1, 2), quiet = TRUE), "tolerance_years")
+  expect_error(GNRS_local(df, dir = dir, history = "at_date", tolerance_years = -1, quiet = TRUE), "tolerance_years")
+})
+
+test_that("a component counts as built only when every one of its files is there", {
+  expect_true(gnrs_is_built("history", dir))
+  expect_true(gnrs_is_built("cshapes", dir))
+  partial <- file.path(tempdir(), "gnrs-partial-history")
+  unlink(partial, recursive = TRUE)
+  dir.create(partial)
+  file.copy(gnrs_history_path("entities", dir), gnrs_history_path("entities", partial))
+  file.copy(gnrs_cshapes_versions_path(dir), gnrs_cshapes_versions_path(partial))
+  expect_false(gnrs_is_built("history", partial))
+  expect_false(gnrs_is_built("cshapes", partial))
+})
+
+test_that("without alternate names a former country is found by its own name only", {
+  with_alt <- gnrs_test_resolve(dir, c("USSR", "Union of Soviet Socialist Republics"))
+  expect_equal(with_alt$entity_key, c("SUHH", "SUHH"))
+  without <- gnrs_test_resolve(dir, c("USSR", "Union of Soviet Socialist Republics"), alternate_names = FALSE)
+  expect_false(without$entity_key[1] == "SUHH")
+  expect_equal(without$entity_key[2], "SUHH")
+})
+
+test_that("former ISO 3166-3 codes resolve, with or without alternate names, and never fuzzily", {
+  r <- gnrs_test_resolve(dir, c("SUHH", "ANHH", "SUHX"))
+  expect_equal(r$entity_key[1:2], c("SUHH", "ANHH"))
+  expect_false(r$entity_key[3] %in% c("SUHH", "ANHH"))
+  strict <- gnrs_test_resolve(dir, c("SUHH", "ANHH"), alternate_names = FALSE)
+  expect_equal(strict$entity_key, c("SUHH", "ANHH"))
+})
+
+test_that("removing a name source rebuilds the history component, and removing CShapes removes it", {
+  # its own cache: the default would rebuild and then strip the file's dir
+  rm_dir <- gnrs_test_backbone(file.path(tempdir(), "gnrs-test-remove"))
+  gnrs_test_cshapes(rm_dir)
+  gnrs_build_history(dir = rm_dir, quiet = TRUE)
+  before <- file.mtime(gnrs_history_path("names", rm_dir))
+  Sys.sleep(1.1)
+  expect_true(GNRS_local_remove(rm_dir, sources = "geonames", ask = FALSE))
+  expect_true(gnrs_is_built("history", rm_dir))
+  expect_gt(as.numeric(file.mtime(gnrs_history_path("names", rm_dir))), as.numeric(before))
+  expect_true(GNRS_local_remove(rm_dir, sources = "cshapes", ask = FALSE))
+  expect_false(gnrs_is_built("cshapes", rm_dir))
+  expect_false(gnrs_is_built("history", rm_dir))
+})
+
+test_that("the history arguments come after quiet, so positional callers still work", {
+  df <- data.frame(user_id = 1, country = "Mexico", state_province = "", county_parish = "")
+  r <- GNRS_local(df, 0.5, TRUE, dir, FALSE, TRUE)
+  expect_equal(r$country, "Mexico")
+  expect_equal(names(formals(GNRS_local))[6], "quiet")
+})
+
+test_that("a state resolved within a successor carries the summary of that resolution", {
+  # the Territory of Hawaii was absorbed into the United States, which the
+  # synthetic reference has, so a state given under it resolves there
+  r <- gnrs_test_resolve(dir, "Territory of Hawaii", "Arizona")
+  expect_equal(r$entity_key, "CSH4")
+  expect_equal(r$subnational_status, "resolved in successor")
+  expect_equal(r$state_province, "Arizona")
+  expect_equal(r$geonameid, r$state_province_id)
+  expect_true(is.finite(r$overall_score))
+  expect_equal(r$overall_score, round((r$match_score_country + r$match_score_state_province) / 2, 2))
+})
diff --git a/tests/testthat/test-local-resolve.R b/tests/testthat/test-local-resolve.R
index 6486ab2..384e904 100644
--- a/tests/testthat/test-local-resolve.R
+++ b/tests/testthat/test-local-resolve.R
@@ -5,6 +5,8 @@ context("offline resolution")
 # match-method labels are the service's.
 
 dir <- gnrs_test_backbone()
+# history = "all" is the default, and the history component needs CShapes
+gnrs_test_cshapes(dir)
 
 test_that("the output has the web service's columns, in its order", {
   r <- gnrs_test_resolve(dir, "United States", "Arizona", "Pima County")
@@ -17,7 +19,12 @@ test_that("the output has the web service's columns, in its order", {
     "gid_2", "match_method_country", "match_method_state_province",
     "match_method_county_parish", "match_score_country",
     "match_score_state_province", "match_score_county_parish", "threshold_fuzzy",
-    "overall_score", "poldiv_submitted", "poldiv_matched", "match_status", "user_id"
+    "overall_score", "poldiv_submitted", "poldiv_matched", "match_status", "user_id",
+    # the service's own columns end here; the components append theirs
+    "alt_division", "alt_division_system", "alt_division_level", "alt_division_extent_known",
+    # history = "all" (the default) appends the historical-division columns
+    "entity_key", "is_historical", "entity_valid_from", "entity_valid_to", "successors",
+    "subnational_resolved_in", "subnational_status", "date_check"
   ))
   expect_equal(r$poldiv_full, "United States@Arizona@Pima County")
   expect_equal(r$country_id, "6252001")
@@ -195,12 +202,19 @@ test_that("a missing backbone is reported rather than erroring", {
 
 test_that("status and citations describe what was built", {
   s <- suppressMessages(GNRS_local_status(dir))
-  expect_equal(s$source, c("gnrs", "gadm", "geonames", "points"))
-  expect_equal(s$built, c(TRUE, FALSE, TRUE, FALSE))
+  expect_equal(s$source, c("gnrs", "gadm", "geonames", "history", "altdiv", "cshapes", "points"))
+  # the history component is built on first use of GNRS_local() (history = "all"), from
+  # the CShapes copy in the cache: CShapes is a component of its own, since nothing
+  # derived from it ships with the package
+  expect_equal(s$built, c(TRUE, FALSE, TRUE, TRUE, TRUE, TRUE, FALSE))
   expect_equal(s$version[1], "database test (2024-01-01), code test")
   cit <- GNRS_local_citations(dir, quiet = TRUE)
-  expect_equal(cit$what, c("method", "software", "source", "source"))
+  expect_equal(cit$what, c("method", "software", "source", "source", "source", "source", "source"))
   expect_true(all(grepl("2024-01-01", cit$citation[3:4])))
+  expect_match(cit$citation[5], "CShapes 2.0")
+  # CShapes is CC BY-NC-SA 4.0: attribution is a condition of use, so it is cited in full
+  expect_match(cit$citation[6], "Alternative and superseded sub-national divisions")
+  expect_match(cit$citation[7], "Mapping the International System")
   bib <- tempfile(fileext = ".bib")
   GNRS_local_citations(dir, bibtex_file = bib, quiet = TRUE)
   expect_true(any(grepl("^@article", readLines(bib))))