In Greek mythology, Agamemnon (/; Greek: Ἀγαμέμνων, Ἀgamémnōn) was a king of Mycenae, the son of King Atreus and Queen Aerope of Mycenae, the brother of Menelaus, the husband of Clytemnestra and the father of Iphigenia, Electra or Laodike (Λαοδίκη), Orestes and Chrysothemis. Legends make him the king of Mycenae or Argos, thought to be different names for the same area. When Helen, the wife of Menelaus, was taken to Troy by Paris, Agamemnon commanded the united Greek armed forces in the ensuing Trojan War.
Upon Agamemnon's return from Troy, he was killed (according to the oldest surviving account, Odyssey 11.409–11) by Aegisthus, the lover of his wife Clytemnestra. In old versions of the story, the scene of the murder, when it is specified, is usually the house of Aegisthus, who has not taken up residence in Agamemnon's palace, and it involves an ambush and the deaths of Agamemnon's followers as well. In some later versions, Clytemnestra herself does the killing, or they act together as accomplices, killing Agamemnon in his own home.
His name in Greek, Ἀγαμέμνων, means "very steadfast", "unbowed". The word comes from *Ἀγαμέδμων from ἄγαν, "very much" and μέδομαι, "think on".