The muster place was at Sardis, and there Greek spies had seen the multitudes assembling and the state and magnificence of the king's attendants. Envoys had come from him to demand earth and water from each state in Greece, as emblems that land and sea were his, but each state was resolved to be free, and only Thessaly, that which lay first in his path, consented to yield the token of subjugation. A council was held at the Isthmus of Corinth, and attended by deputies from all the states of Greece to consider of the best means of defense. The ships of the enemy would coast round the shores of the Aegean sea, the land army would cross the Hellespont on a bridge of boats lashed together, and march southwards into Greece. The only hope of averting the danger lay in defending such passages as, from the nature of the ground, were so narrow that only a few persons could fight hand to hand at once, so that courage would be of more avail than numbers. The first of all these passes was called Tempe, and a body of troops was sent to guard it; but they found that this was useless and impossible, and came back again. The next was at Thermopylae. Look in your map of the Archipelago, or Aegean Sea, as it was then called, for the great island of Negropont, or by its old name, Euboea. It looks like a piece broken off from the coast, and to the north is shaped like the head of a bird, with the beak running into a gulf, that would fit over it, upon the main land, and between the island and the coast is an exceedingly narrow strait. The Persian army would have to march round the edge of the gulf. They could not cut straight across the country, because the ridge of mountains called Ceta rose up and barred their way. Indeed, the woods, rocks, and precipices came down so near the seashore, that in two places there was only room for one single wheel track between the steeps and the impassable morass that formed the border of the gulf on its south side. These two very narrow places were called the gates of the pass, and were about a mile apart. There was a little more width left in the intervening space; but in this there were a number of springs of warm mineral water, salt and sulphurous, which were used for the sick to bathe in, and thus the place was called Thermopylae, or the Hot Gates. A wall had once been built across the western-most of these narrow places, when the Thessalians and Phocians, who lived on either side of it, had been at war with one another; but it had been allowed to go to decay, since the Phocians had found out that there was a very steep narrow mountain path along the bed of a torrent, by which it was possible to cross from one territory to the other without going round this marshy coast road.