What was the first (known) maths mistake?

Thanks to Waterstones for choosing Humble Pi as a 'top 100' paperback of the year.
https://www.waterstones.com/book/humble-pi/matt-parker/9780141989143

Signed copies are available at Maths Gear. It's cheaper at Waterstones, but not signed. You choose!
https://mathsgear.co.uk/collections/books/products/humble-pi-signed-paperback

Thanks to Robert Englund and the Free University of Berlin for producing Archaic Bookkeeping. What a niche but amazing book. But be warned: copies are not cheap.
https://www.amazon.co.uk/Archaic-Bookkeeping-Techniques-Economic-Administration/dp/0226586596
https://books.google.co.uk/books/about/Archaic_Bookkeeping.html?id=YBAzXV4YtQ8C&redir_esc=y

Hey look, Kushim has their own wikipedia page!
https://en.wikipedia.org/wiki/Kushim_(Uruk_Period%29

CORRECTIONS
- None spotted yet. Let me know if you locate any mistakes.

Thanks to Penguin Random House for supporting this video.

As always: thanks to Jane Street who support my channel. They're amazing.
https://www.janestreet.com/

And thanks to all my Patreon legends. You allow me to take risks and make different videos like this. Will the internet like an all-animated Stand-up Maths video? We'll find out!
https://www.patreon.com/standupmaths

Animation by William Marler
Music and sound by Howard Carter (including the SUM-erian theme remix)
Written and narrated by Matt Parker
Beer by Kushim and Nisa

MATT PARKER: Stand-up Mathematician
Website: http://standupmaths.com/
US book: https://www.penguinrandomhouse.com/books/610964/humble-pi-by-matt-parker/
UK book: https://mathsgear.co.uk/products/5b9fa76f230ffa140094dc43
Nerdy maths toys: http://mathsgear.co.uk/