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 backing of Egypt. However Aratus, the leader of the Achaean League, decided to ally with Achaea's enemy, Macedonia. With Egypt deciding to cut financial aid Cleomenes decided to risk all on one battle. In the resulting Battle of Sellasia in 222 BC, Cleomenes was defeated by the Achaeans and Macedonia. Antigonus III Doson, the king of Macedon ceremonially entered Sparta with his army, something Sparta had never endured before. The ephors were restored, whilst the kingship was suspended. At the beginning of the Social War in 220 BC, envoys from Achaea unsuccessfully attempted to persuade Sparta to take the field