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
Thermopylae shoreline has also advanced over the centuries because of the sedimentary deposition. The level of the Malian Gulf was also significantly higher during prehistoric times and the Spercheios River was significantly shorter. Its shoreline advanced by up to 2 kilometers between 2500 BC and 480 BC but still has left several extremely narrow passages between the sea and the mountains. The narrowest point on the plain, where the Battle of Thermopylae was probably fought, would have been less than wide. Between 480 BC and the 21st century, the shoreline advanced by as much as in places, eliminating the narrowest points