Borders before 1000 CE are the most recent snapshot at or before the date, from
Historical Basemaps
(aourednik, GPL-3.0; the derived border data is GPL-3.0 too, simplified for the web;
its author warns they are approximate and disputed). Borders 1000-2024: Cliopatria
(Seshat Global History Databank), licensed
CC BY 4.0. Source:
github.com/Seshat-Global-History-Databank/cliopatria,
archived at zenodo.org/records/13363121; described in
doi.org/10.1038/s41597-025-04516-9.
Changes made: simplified, filtered (relations and grouping rows removed, identical consecutive
geometries merged) and re-encoded. Years after 2024 show the 2024 borders. From 1000 to 1900 a faint
Historical Basemaps layer fills areas Cliopatria leaves unmapped. Coastlines: Natural Earth (public domain).
Additional polities: hand-curated, approximate (each carries its own source note).
Borders are approximate and one version of a contested record. Event dates and places were written from general knowledge;
those of the prominent events and of most later additions were checked against Wikipedia, the rest (including about 431 month and day dates) were not.
War-front lines are hand-read from Wikipedia campaign maps and text, accurate to tens of kilometres. City populations are approximate estimates
(Chandler 1987, Modelski 2003, Wikipedia, national censuses; each city's popup cites the source of its own figures). Descriptions are paraphrased from Wikipedia (CC BY-SA);
popup images are loaded from Wikipedia and keep their own Wikimedia licences (see the linked article). Polity "attestation confidence" lines come from a
research pass with Wikipedia links, not a scholarly assessment. The pre-1000 border data is GPL-3.0 and is served as plain JSON under
data/, which is its source form. Full licence notice: data/NOTICE.txt.
Keys. ← → step: from 1500 CE on a month, Shift a year, Alt or Ctrl a day; before 1500 one slider step (Shift = 10 steps). PgUp/PgDn a month, [ ] jump a basemap page, / search cities (any of their names) and events, scroll or pinch to zoom, click a region for details.