Battle of Thermopylae at Thermopylae, the Persians sent a mounted scout to reconnoitre. The Greeks allowed him to come up to the camp, observe them, and depart. Xerxes found the scout's reports of the size of the Greek force, and that the Spartans were indulging in callisthenics and combing their long hair, laughable. Seeking the counsel of Demaratus, an exiled Spartan king in his retinue, Xerxes was told the Spartans were preparing for battle, and it was their custom to adorn their hair when they were about to risk their lives. Demaratus called them "the bravest men in Greece" and warned the Great
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