Cleomenean War

The Battle of Sellasia, fought in the summer of 222 BC on the northern frontier of Laconia, was a decisive engagement of the Cleomenean War in which the combined Macedonian and Achaean League forces under Antigonus III Doson defeated Sparta under King Cleomenes III. Sparta's losses of approximately 5,800 against a combined Macedonian-Achaean force of around 28,000 against Sparta's 20,000 indicate the scale of the Spartan defeat. The battle ended Spartan resistance in the conflict and secured Macedonian and Achaean dominance over the Peloponnese, with the fall of Laconia's northern frontier leaving Sparta itself exposed. Cleomenes III and his co-commander Eucleidas were unable to hold the line against the larger coalition force assembled by Antigonus.