What is bisclavret?

Bisclavret is a medieval Breton lay written by the poet Marie de France. It tells the story of a nobleman who is transformed into a werewolf, or loup-garou, every week due to a curse placed upon him by his wife. The nobleman's loyal friends eventually discover his secret and help him regain his human form and seek revenge against his deceitful wife. The poem explores themes of loyalty, betrayal, and the consequences of breaking trust. Bisclavret is one of the earliest known werewolf stories in literature and is considered a classic of medieval French literature.