Sources and licensing

Every page on What's On This Date is assembled from a small number of named sources. This page says which, what licence each one carries, and what that means if you want to reuse anything.

The sources

Wikipedia
Supplies the on-this-day selections and the article extracts used as entry summaries and encyclopedia panels. Text is available under CC BY-SA 4.0. Each entry links to the article it came from.
Wikidata
Supplies structured facts: exact birth and death dates, places, occupations, awards, and the relations that build the “what came before and after” chain. Wikidata is released under CC0 and carries no reuse conditions.
Wikimedia Commons
Supplies images, rehosted here as WebP for speed. Creator and licence are shown with each image where the source records them. Files tagged non-free or fair-use are skipped rather than shown.
Our own editorial entries
Written here and marked “Written by our editors”. These are copyright What's On This Date. Everything computed from the calendar — day numbers, weekdays, ages, anniversaries — is generated by this site.

Reusing material from this site

  • Wikipedia-derived text: attribute Wikipedia, link the article, and license your adaptation under CC BY-SA 4.0.
  • Wikidata-derived facts: no conditions, though a credit is appreciated.
  • Images: follow the licence shown with the individual image and credit its creator.
  • Our editorial text and page layouts: ask first.

Citing a page

“What happened on September 12”, What's On This Date, https://example.com/history/september-12, accessed 13 September 2026.

For an individual claim, follow the source link on the entry and cite the underlying source as well as this page. The developer page documents the JSON endpoints if you would rather take the data directly.

What we do not do

  • We do not reprint whole articles. Entries are short summaries that link to the source.
  • We do not generate facts with AI. See how this site works for where AI is used.
  • We do not hotlink images from other sites; everything shown here is rehosted and credited.

Licensing questions

What licence applies to the text?

Text adapted from Wikipedia is available under Creative Commons Attribution-ShareAlike 4.0. Reuse it with attribution and share any adaptation under the same licence. Facts taken from Wikidata are released under CC0 and carry no conditions.

Who owns the images?

Images are rehosted from Wikimedia Commons and converted to WebP. Each image shows its creator and licence where the source records them. Files that carry a non-free or fair-use tag are not used.

How should I cite a page?

Cite the page title, this site as the publisher, the page address and the date you read it. For the underlying claim, follow the source link on the entry and cite that as well.

Can I reuse the data in bulk?

The public JSON endpoints are documented on the developer page. Keep the attribution and licence conditions with the data, and be reasonable about request rates.