Which ancient document records kings reigning for tens of thousands of years?

The Sumerian King List survives in several copies, the best of them a small clay prism in the Ashmolean from around 1800 BC. It sets out the kings of Mesopotamia in a single sequence, moving from city to city with the formula that kingship was taken to the next place - and it opens with rulers before the flood whose reigns run to 28,800 years, 36,000 years, and so on, for a total of something like 241,000 years.

The numbers are not a mistake or a fantasy exactly. Reigns shorten sharply after the line where the flood sweeps over the land, and by the time the list reaches historically attested kings the figures are unremarkable. Gilgamesh of Uruk appears with a reign of 126 years, sitting on the boundary between the two registers.

The important thing is that it is not a chronicle. It presents as a single relay of legitimate rule what was in fact a landscape of rival cities ruling at the same time. That is the document's purpose: it is an argument that there is only ever one true kingship, held by one city at a time, and by implication held now by whoever commissioned the copy. It is propaganda in the shape of a list, which is a form that has never gone out of use.