Agamemnon, king of Mycenae, one of the foremost figures in the Iliad, was the son of Atreus according to Homer, but his grandson according to others. He commanded the combined forces of Greece at the siege of Troy. He married Clytemnestra, half sister of Helen, the wife of his brother Menelaus. The Grecian fleet being detained at Aulis, its sailing place, by unfavorable winds, the priest Calchas declared that the gods must be propitiated by the sacrifice of the king's daughter Iphigenia, on account of his having offended Diana by killing her favorite stag. Agamemnon yielded to the will of the gods, but his daughter was saved by Diana. His quarrel with Achilles forms one of the most interesting portions of the Iliad, which opens with an account of it. On his return from Troy he was murdered by his wife, who had formed an adulterous relation with Aegisthus during his absence, and avenged by his son Orestes.