As the first play of The Orestia opens, the Trojan war is ending. The watchman, straggling the Atreidae’s roof dogwise, sees the beacon signaling victory in Ilium. Agamemnon returns home with Cassandra, a prophetess and daughter of Priam, as a concubine. He has been gone for ten years, with the human sacrifice of his daughter Iphigenia as his farewell. Once home he is greeted by the duplicitous Clytaemestra. She conspires with her lover Aegisthus to kill Agamemnon and seize the reins of power.