Medievalist Emir O. Filipovic was flipping through fifteenth century manuscripts at the State Archives in Dubrovnik, Croatia — your average light reading — when he came across something rather remarkable on one of the pages: Feline paw prints.

Filipovic's discovery lay dormant until it was picked up by book historian Erik Kwakkel, who was in turn brought to the attention of the public by "America's Veterinarian" Dr. Marty Becker.

"Has your cat ever walked across your keyboard?" asks Dr. Becker on his Facebook page, where the image has been shared thousands of times. "Well, it's not a new problem. Medieval book historian Erik Kwakkel recently Tweeted this photo of a 15th century book with... you guessed it... cat paw prints in ink on the pages! We're part of a long and glorious historical movement, friends."

As if you needed any additional proof that cats have always been assholes.

[H/T: Ouest France, 22words, photo via Facebook]