Creusa (krēōō´sə), in Greek mythology. 1 Daughter of Erechtheus and wife of Xuthus. Her sons, Achaeus by Xuthus, and Ion by Xuthus or Apollo, are the ancestors of the Achaeans and the Ionians. 2 Princess of Corinth: see Jason and Medea. 3 Daughter of Priam and wife of Aeneas. She died fleeing from Troy.