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
History of Sparta Persians at the battle of Plataea. The decisive Greek victory at Plataea put an end to the Greco-Persian War along with Persian ambition of expanding into Europe. Even though this war was won by a pan-Greek army, credit was given to Sparta, who besides being the protagonist at Thermopylae and Plataea, had been the de facto leader of the entire Greek expedition. In the same year a united Greek fleet under the Spartan King, Leotychidas, won the Battle of Mycale. When this victory led to a revolt of the Ionian Greeks it was Sparta that rejected their admission to the