Remember that Medieval manuscript with the centuries-old pawprints? Today's proof that cats have always loved ruining things comes in the form of cat pee.

In 1420 a scribe in what is now the Netherlands discovered that a cat had urinated on a document he was working on. Instead of scrapping the work, he added an addendum to the piece, with some words of wisdom for future cat owners. While originally written in Latin, in English the text reads

Here is nothing missing, but a cat urinated on this during a certain night. Cursed be the pesty cat that urinated over this book during the night in Deventer and because of it many others [other cats] too. And beware well not to leave open books at night where cats can come.