Aegusthus, king of Mycenae, son of Thyes-tes and cousin to Agamemnon, He formed an adulterous connection with Agamemnon's wife Clytemnestra during his absence at Troy, and contrived his murder on his return. Eight years later he was slain by Orestes, the son of Agamemnon. Writers later than Homer tell a frightful story of incest and crime about Aegisthus and his family. (See Atreus.)