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