Sources & Attribution

This site is built almost entirely from other people's work. This page records whose, and under what terms.

Event data — Wikidata

All 111,389 events come from Wikidata: the event titles, the one-line descriptions, the dates, the date precisions and the coordinates. Wikidata content is released under the Creative Commons CC0 1.0 Universal Public Domain Dedication, which places it in the public domain and imposes no attribution requirement.

We credit it anyway. A public-domain dedication removes the obligation, not the debt: this site would not exist without the people who entered those statements, and readers deserve to know where the claims come from and where to check them.

Wikipedia

Each event links to its English Wikipedia article where one exists, and to its Wikidata item otherwise. No Wikipedia article text is reproduced on this site. Wikipedia is used only as a link destination and as a key for matching items; the descriptions you see are Wikidata's own, not extracts from articles. Wikipedia's CC BY-SA 4.0 licence therefore does not attach to anything published here.

Map geometry — Natural Earth

Country outlines come from world-atlas, a TopoJSON build of Natural Earth. Natural Earth is in the public domain.

Note that the map shows present-day borders at every point on the timeline. Drawing historically accurate borders for 5,000 years is a far harder problem than this site solves, so the outlines are a backdrop for placing events, not a claim about who governed what.

Software

• D3 — visualisation library, ISC licence.
• topojson-client — TopoJSON decoding, ISC licence.

Corrections

Because the data is Wikidata's, factual corrections are best made at the source: edit the item on Wikidata and the correction reaches every project that uses it, not just this one. Each event page links directly to the item it came from.