Through the Pass of Thermopylae lay the entrance from the north to the south of Greece. It was this pass that the Greeks determined to hold against the Persians when they withdrew from the Pass of Tempe. The Pass of Thermopylae was about a mile long and the narrow road ran between the mountains and the sea. At each end of the pass the mountains were sheer cliffs, descending so close to the sea that the only pathway was a mere strip of sand. To enter the pass, at either end, it was necessary to go through a narrow entrance called Pylae or the Gates. In the road between the Pylae or Gates there were hot springs. The Greek word for hot is thermos, and that is how the pass came to be named Thermopylae or Hot-Gates. At the narrowest part of the pass stood an old broken-down wall, and this wall was repaired by the order of Leonidas, King of Sparta, that it might form a defence against the enemy. A short distance from the mainland lay the island of Euboea, the strait between being at one place only two and a half miles in breadth. Here the Greek fleet took up its position under the command of the Spartan Eurybiades, Themistocles being second in command. Themistocles would have held the chief command had not some of the States refused to serve under an Athenian admiral. The land army was led by Leonidas, one of the kings of Sparta. But because this was now the month of June 480 B.C., the time when the Olympic games were held, many of the Spartans did not march with Leonidas to Thermopylae. For although the country was in danger, the games, being also religious rites, must be held as usual, and numbers of brave soldiers stayed at home to take part in the festival. When Leonidas set out on his march to defend the entrance to the south of Greece, he had with him only three hundred Spartans. On the way to Thermopylae he was joined by troops from other States, so that when he reached the pass he was at the head of seven thousand men. Now there was only one narrow hill track by which the enemy could reach the rear of the Spartans, and strangers to the country were little likely to find it. Yet Leonidas bade the Phocians, who lived in the district, guard well this narrow footpath. He would leave nothing to chance. When Xerxes with his great army reached Thermopylae, he was told that it was in the hands of a small band of Spartans, under king Leonidas. The tidings did not disturb the Persian monarch, he was sure that the Spartans would soon leave their post, when they saw his great army. But the Spartans did not retreat, although they could see plainly the vast hordes that had come against them.