What is "aegisthus"

Aegisthus (; ; also transliterated as Aigisthos) is a figure in Greek mythology. He was the son of Thyestes and his daughter, Pelopia. The product of an incestuous union motivated by his father's rivalry with the house of Atreus for the throne of Mycenae, Aegisthus murdered Atreus to restore his father to power. Later, he lost the throne to Atreus's son Agamemnon.

While Agamemnon was at the Trojan war, Aegisthus became the lover of the king's estranged wife Clytemnestra. The couple killed Agamemnon on his return. He became king of Mycenae for seven years before he was killed in his turn by Agamemnon's son Orestes.