A son of Atreus, king of Mycenae and general-in-chief of the Greeks in the Trojan war, represented as a man of stately presence and a proud spirit. On the advice of the soothsayer Calchas sacrificed his daughter Iphigenia for the success of the enterprise he conducted. He was assassinated by Aegisthus and Clytaemnestra, his wife, on his return from the war. His fate and that of his house is the subject of Aeschylus' trilogy "Oresteia."