Aegisthus (ējĭsˈthəs) [key], in Greek mythology, according to most legends the incestuous offspring of Thyestes and his daughter Pelopia. At Thyestes' behest Aegisthus revenged the murder of his brothers by killing his uncle Atreus. Later, he was known as the lover of Clytemnestra and aided her in the murdering of her husband, Agamemnon. He was killed in revenge by Clytemnestra's son, Orestes.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.
More on Aegisthus from Fact Monster:
See more Encyclopedia articles on: Folklore and Mythology