These Thessalian envoys proclaimed their willingness to assist the confederates in the defence of their fatherland, but represented the imminence of the danger to Thessaly, and demanded an immediate supply of forces. "Without this," they said, "we cannot exert ourselves for you, and our inability to assist you will be our excuse, if we provide for our own safety." Aroused by these exhortations, the confederates commenced their military movements. A body of infantry passed the Euripus, entered Thessaly, and encamped amid the delights of the vale of Tempe. Here their numbers, in all ten thousand heavy-armed troops, were joined by the Thessalian horse. The Spartans were led by Euaenetus. Themistocles commanded the Athenians. The army did not long, however, remain in the encampment. Alexander, the king of Macedon, sent confidentially advising their retreat, and explaining accurately the force of the enemy. This advice concurred with the discovery that there was another passage into Thessaly through the higher regions of Macedonia, which exposed them to be taken in the rear. And, in truth, it was through this passage that the Persian army ultimately marched. The Greeks, therefore, broke up the camp and returned to the Isthmus. The Thessalians, thus abandoned, instantly treated with the invader, and became among the stanchest allies of Xerxes. It was now finally agreed in the Isthmian congress, that the most advisable plan would be to defend the pass of Thermopylae, as being both nearer and narrower than that of Thessaly. The fleet they resolved to send to Artemisium, on the coast of Histiaeotis, a place sufficiently neighbouring Thermopylae to allow of easy communication. Never, perhaps, have the Greeks shown more military skill than in the choice of these stations. But one pass in those mountainous districts permitted the descent of the Persian army from Thessaly, bounded to the west by steep and inaccessible cliffs, extending as far as Mount Oeta; to the east by shoals and the neighbouring sea. This defile received its name Thermopylae, or Hot Gates, from the hot-springs which rose near the base of the mountain. In remote times the pastoral Phocians had fortified the place against the incursions of the Thessalians, and the decayed remains of the wall and gates of their ancient garrison were still existent in the middle of the pass; while, by marsh and morass, to render the place yet more impassable, they had suffered the hot-springs to empty themselves along the plain, on the Thessalian side, and the quagmire was still sodden and unsteady. The country on either side the Thermopylae was so contracted, that before, near the river Phoenix, and behind, near the village of Alpeni, was at that time space only for a single chariot. In such a pass the numbers and the cavalry of the Mede were rendered unavailable; while at the distance of about fifteen miles from Thermopylae the ships of the Grecian navy rode in the narrow sea, off