"Bisclavret" ("The Werewolf") is one of the twelve Lais of Marie de France written in the 12th century. Originally written in French, it tells the story of a Lord who is trapped in lupine form by the treachery of his wife. The tale shares a common ancestry with the comparable Lay of Melion, and is probably referenced in Sir Thomas Malory's Le Morte d'Arthur with the tale of Sir Marrok, who has a similar story. Source: Wikipedia (en)