Battle of Plataea other. The Allies initially adopted a strategy of blocking land and sea approaches to southern Greece. Thus, in August 480 BC, after hearing of Xerxes' approach, a small Allied army led by Spartan King Leonidas I blocked the Pass of Thermopylae, while an Athenian-dominated navy sailed to the Straits of Artemisium. Famously, the massively outnumbered Greek army held Thermopylae for three days before being outflanked by the Persians, who used a little-known mountain path. Although much of the Greek army retreated, the rearguard, formed of the Spartan and Thespian contingents, was surrounded and annihilated. The simultaneous Battle of Artemisium, consisting
Battle of Thermopylae (279 BC) his forces, who were then free to ravage the country. After these expeditions returned home, Brennus urged and persuaded them to mount a third united expedition against central Greece, led by himself and Acichorius. A Greek coalition made up of Aetolians, Boeotians, Athenians, Phocians, and other Greeks north of Corinth took up positions at the narrow pass of Thermopylae, on the east coast of central Greece. During the initial assault, Brennus' forces suffered heavy losses. Hence he decided to send a large force under Acichorius against Aetolia. The Aetolian detachment, as Brennus hoped, left Thermopylae to defend their homes. The