Son of Agamemnon and Clytemnestra, who revenged his father's death seven years after Clytemnestra and her lover Aegisthus had murdered him. Being just a boy when the tragic incident happened, he was sent away by his sister Electra, and grew up under the protection of King Strophius of Phocis, who was also his uncle. Electra kept sending him messages from Mycenae where she encouraged him to avenge his father, and after consulting the oracle in Delphi, he went ahead with it.
His best friend and companian was king Phocis's son Pylades, who married Electra after helping Orestes kill his mother and her lover. Because matricide was a serious crime, Orestes was persecuted by the Erinyes and had to flee from place to place. He ended up in Athens, where he was brought before the Aeropagus and Athena. He was aquitted but kept being stalked by the Erinyes. Not until he brought back his sister Iphigenia was he left alone by the avenging goddesses.
Orestes then ruled Mycenae, and through his marriage with Menelaus and Helens daughter Hermione, whom he won battling Achilles son Neotolemus, he united his kingdom with Sparta. Together they had the son Tisamenus.