Thyestes killed Atreus. While Thyestes ruled Mycenae, the sons of Atreus, Agamemnon and Menelaus, were exiled to Sparta. There, King Tyndareus accepted them as the royalty that they were. Shortly after, he helped the brothers return to Mycenae to overthrow Thyestes, forcing him to live in Cytheria, where he died. As a token of good will and allegiance, King Tyndareus offered his daughters to Agamemnon and Menelaus as wives, Clytemnestra and Helen respectively. When Agamemnon left Mycenae for the Trojan War, Aegisthus seduced Agamemnon's wife, Clytemnestra, and the couple plotted to kill her husband upon his return. They succeeded, killing Agamemnon
Polydorus of Sparta unique constitution of Sparta due to a lack of sources, so analyzing the reliability of Plutarch on Polydorus is difficult. Pausanias, another Greek writing under Roman rule, gave a detailed account of the First Messenian War, a conflict between Sparta and their neighbors who would soon become their slaves. He tells us that Polydorus was in charge of the left side of the Spartan forces at Ampheia, and that his co-king Theopompus was in command of the right flank (more influential for Spartan offensive tactics). Polydorus of Sparta Polydorus (Polydoros) (; reigned from c. 700 to c. 665 BC) was