Troilus and Criseyde (circa 1380-87) is Geoffrey Chaucer's classic poem in rhyme royal (rime royale, seven line stanzas rhyming ababbcc) re-telling the tragic love story of Troilus, a Trojan prince, and Criseyde. Scholarly consensus is that Chaucer completed Troilus and Criseyde by the mid 1380's. Many Chaucer scholars regard this as his best work, even including the better known but incomplete Canterbury Tales. The tragedy of Troilus and Criseyde is one of the greatest narrative poems in English literature. Set during the siege of Troy, it tells how the young knight Troilus, son of King Priam, falls in love with Criseyde, a beautiful widow. Brought together by Criseyde's uncle, Pandarus, the lovers are then forced apart by the events of war, which test their oaths of fidelity and trust to the limits.

Described by Barry Windeatt as Chaucer's "most ambitious single achievement, his masterpiece," Troilus and Criseyde is the first work in English to depict human passion with such sympathy and understanding.