Olympic Straits, that is, at the pass
between Olympus and Ossa; and to do that, it would be necessary to send
a strong force immediately to take possession of the pass. If, on the
contrary, they decided _not_ to defend Thessaly, then the pass of
Thermopylae would be the point at which they must make their stand, and
in that case Thessaly must be at liberty to submit on the first Persian
summons.

The Greeks, after consultation on the subject, decided that it would be
best for them to defend Thessaly, and to take their stand, accordingly,
at the Straits of Olympus. They immediately put a large force on board
their fleet, armed and equipped for the expedition. This was at the time
when Xerxes was just about crossing the Hellespont. The fleet sailed
from the port of Athens, passed up through the narrow strait called
Euripus, lying between the island of Euboea and the main land, and
finally landed at a favorable point of disembarkation, south of
Thessaly. From this point the forces marched to the northward until they
reached the Peneus, and then established themselves at the narrowest
part of the passage between the mountains, strengthened their position
there as much as possible, and awaited the coming of the enemy. The
amount of the force was ten thousand men.

They had not been here many days before a messenger came to them from
the King of Macedon, which country, it will be seen, lies immediately
north of Thessaly, earnestly dissuading them from attempting to make a
stand at the Vale of Tempe. Xerxes was coming on, he said, with an
immense and overwhelming force, one against which it would be utterly
impossible for them to make good their defense at such a point as that.
It would be far better for them to fall back to Thermopylae, which, being
a narrower and more rugged pass, could be more easily defended.

Besides this, the messenger said that it was possible for Xerxes to
enter Thessaly without going through the Vale of Tempe at all. The
country between Thessaly and Macedon was mountainous, but it was not
impassable, and Xerxes would very probably come by that way. The only
security, therefore, for the Greeks, would be to fall back and intrench
themselves at Thermopylae. Nor was there any time to be lost. Xerxes was
crossing the Hellespont, and the whole country was full of excitement
and terror.

The Greeks determined to act on this advice. They broke up their
encampment at the Olympic Straits, and, retreating t