It was Themistokles, the most fightproofen warlord of Athen, who took the Thermopyls - a small pathway between hills on the one and the sea on the other side - as the best place for the first clash against the incoming persians. At August 480 BC Leonidas, one of the two kings of sparta, behest to build an outpost there. The Phocis build a wall at the smallest point of the pathway, Leonidas places most of his men behind it. Also 1000 Phocis watched s small path wich led behind the the wall of the greeks.