Cassandra was the daughter of King Priam and Queen Hecuba of Troy. She was a prophectic priestess of Apollo, who taught her the secrets of prophecy upon the condition he may sleep with her. When she refused, he cursed her so that her propechies would be true but nobody would believe her. She taught her brother, Helenus, divination. She prophesised the fall of Troy, the use of the Trojan Horse and her own death. After the war, she was taken by Agamemnon as a concubine. She witnessed his death upon their return to Mycenae and knew that she was to be killed by Aegisthus and Clytaemnestra.