Il Filostrato is a long narrative poem in Italian from Boccaccio's early years. It tells of Troilo, a young prince of Troy, who falls in love with the widow Criseida, and follows their affair against the background of the Trojan war. The poem explores desire, trust and the pain of separation, and is thought to reflect the poet's own feelings. It is important because it became the main source for Chaucer's Troilus and Criseyde, and so for later versions of the story.