In Greek mythology, Atreus (Ancient Greek: Ἀτρεύς, [a.trěu̯s] lit. 'fearless') was a king of Mycenae in the Peloponnese, the son of Pelops and Hippodamia, and the father of Agamemnon and Menelaus. His descendants became known collectively as the Atreidae (Ancient Greek: Ἀτρείδαι Atreidai).
Atreus and his brother Thyestes were exiled by their father for murdering their half-brother Chrysippus in their desire for the throne of Olympia. They took refuge in Mycenae, where they ascended to the throne in the absence of King Eurystheus, who was fighting the Heracleidae. Eurystheus had meant for their stewardship to be temporary, but it became permanent after his death in battle, which ended the rule of the Perseid dynasty in Mycenae.
