Clytemnestra, in Greek mythology, queen of Mycenae, a city in the Pelopónnisos (Peloponnesus), and wife of King Agamemnon. The daughter of Tyndareus, king of Sparta, and his wife Leda, she bore Agamemnon four children: Electra, Iphigenia, Orestes, and Chrysothemis. After Agamemnon sacrificed Iphigenia so that his ships could sail to Troy, Clytemnestra's love for her husband turned to hatred; while he led the Greek forces in the Trojan War, she took Aegisthus as her lover. When Agamemnon returned in triumph with the Trojan princess Cassandra, Clytemnestra sought revenge for the death of Iphigenia, and, with the help of Aegisthus, she killed both her husband and his Trojan mistress. She and her lover ruled for seven years until they were both slain by Orestes, who had been commanded by the god Apollo to avenge the death of his father.