The Pass of Thermopylae battlefield of 480 BC as it appears today from the modern road which in ancient times was flooded by the Malian Gulf, that has since receded 5km NE. In 480 BC, an alliance of Greek city-states led by Spartan King Leonidas faced an enormous invading Persian army at the pass of Thermopylae. The Persians, led by King Xerxes, had an overwhelming numerical advantage of warriors and expected an easy victory. The 300 Spartans held off the Persians for three days before finally being overrun. This battle has been cited as one of historys most famous last stands. The battlefield is much overgrown today and must have looked very different in ancient times. Panorama showing Mt. Kallindromos above the battle slopes.