Bisclavret is a story by Marie de France written in the twelfth century and following the titular Bisclavret and the shenanigans he has to put up with due to his particular branch of lycanthropy.
A quick synopsis:
Bisclavret is a baron who vanishes three days out of every week for reasons nobody knows. One day, his wife finally manages to wriggle the answer out of him: he is a werewolf, and he leaves so he can go off into the woods and get furry in peace. He must go out, hide his clothes, do his thing, then find his clothes again so that he may return to human shape.
His wife suddenly realizes that there are some problems that marital counseling will not cover, and immediately calls up her knightly boyfriend over so they can figure out a way to get hubby out of the picture.
The next time Bisclavret goes off for his time of the week, the knight follows him and steals his clothes, trapping him in wolf form.
A year passes. One day, the king is out hunting, and his dogs manage to corner a wolf. As soon as the wolf sees the king, it immediately begins licking his feet and even bows like a courtier. The king is tickled pink and decides to take the wolf home because- hey. King.
Meanwhile, back home, the wife of the missing baron and her boyfriend have gotten married. He and all the other local barons are invited to the king's place for a royal shindig. As soon as the wolf sees him, it immediately attacks him.
They manage to haul the wolf off of the knight/baron/backstabbing traitor, but considering that this is the first time the wolf has ever attacked anybody, people suspect that maybe the knight has done something to piss it off.
Later, the king goes to visit Bisclavret's old barony where his wife still lives. She goes out to meet the king and his entourage, and the wolf goes berserk. This time, he manages to tear off her nose before they can pull him off.
One of the courtiers points out how she is married to the knight the wolf attacked earlier, how they are the only two people the wolf has ever attacked, how this woman is the wife of one of his missing barons, and how- hey, this is 12th century Brittany. Even a wolf's opinion is worth more than that of a woman's.
The woman is questioned and a little bit of torture later, she confesses to everything and gives back the stolen clothing she'd been hiding away for. . . some. . . reason. The wolf and the clothes are left alone in the bedroom, and Bisclavret comes out a few minutes later, looking a little worn but no worse for the wear.
The king- who must by now be feeling at least a little bit awkward- reinstates all of Biscky's lands and titles, banishes the knight and the wife, and then presumably goes off to go kill wolves now that he knows it's okay again.
So Bisclavret goes on the rest of his days as best friends with the king and his wife and her boyfriend go off and have kids, all of which are born without noses. Because genetics totally works that way. The end.