And it's a monk expressing his displeasure at an abbot. In the margins of a guide to moral conduct. Because of course.
Technically, "fuck" appeared two times before this. In 1500, it was used in a satirical poem to describe some friars. In that case, nothing like "fuck" was actually written out. Instead, the word was hidden in a code. And in 1513, it appeared in a Scottish poem as "fukkit."