Cressida (/ˈkrɛsɪdə/; also Criseida, Cresseid or Criseyde) is a character who appears in many Medieval and Renaissance retellings of the story of the Trojan War. She is a Trojan woman, the daughter of Calchas, a Greek seer. She falls in love with Troilus, the youngest son of King Priam, and pledges everlasting love, but when she is sent to the Greeks as part of a hostage exchange, she forms a liaison with the Greek warrior Diomedes. In later culture she becomes an archetype of a faithless lover.
The character's name is derived from that of Chryseis (GEN ), a character who appears in the Iliad but has no connection with Troilus, Diomedes or Calchas. Indeed, the story of Troilus and Cressida does not appear in any Greek legends but was invented by the twelfth century French poet Benoît de Sainte-Maure in the Roman de Troie. The woman in the love triangle is here called not Cressida but Briseida, a name derived from that of Briseis, a different character in the Iliad, who again is neither related to Calchas nor involved in any love affairs with Troilus or Diomedes. Initially, after the Roman appeared, other authors who refer to the story, for example, Azalais d'Altier in her poem Tanz salutz e tantas amors and Guido delle Colonne in his Historia destructionis Troiae, continue to use names derived from that of Briseis.