But "Remember Athens!" was always in his mind.
So for ten years he and his son Xerxes prepared a vast armada against
which they thought no other force on earth could stand. But, like the
Spanish Armada against England two thousand years later, this Persian
host was very much stronger ashore than afloat. Its army was so vast
that it covered the country like a swarm of locusts. At the
world-famous pass of Thermopylae the Spartan king, Leonidas, waited for
the Persians. Xerxes sent a summons asking the Greeks to surrender
their arms. "Come and take them," said Leonidas. Then wave after wave
of Persians rushed to the attack, only to break against the dauntless
Greeks. At last a vile traitor told Xerxes of another pass (which the
Greeks had not men enough to hold, though it was on their flank). He
thus got the chance of forcing them either to retreat or be cut off.
Once through this pass the Persians overran the country; and all the
Spartans at Thermopylae died fighting to the last.

Only the Grecian fleet remained. It was vastly out-numbered by the
Persian fleet. But it was manned by patriots trained to fight on the
water; while the Persians themselves were nearly all landsmen, and so
had to depend on the Phoenicians and colonial Greek seamen, who were
none too eager for the fray. Seeing the Persians too densely massed
together on a narrow front the Greek commander, Themistocles, attacked
with equal skill and fury, rolled up the Persian front in confusion on
the mass behind, and won the battle that saved the Western World. The
Persians lost two hundred vessels against only forty Greek. But it was
not the mere loss of vessels, or even of this battle of Salamis itself,
that forced Xerxes to give up all hopes of conquest. The real reason
was his having lost the command of the sea. He knew that the
victorious Greeks could now beat the fighting ships escorting his
supply vessels coming overseas from Asia Minor, and that, without the
constant supplies of men, arms, food, and everything else an army
needs, his army itself must wither away.

Two hundred and twenty years later the sea-power of the Roman West beat
both the land- and sea-power of the Carthaginian East; and for the very
same reason. Carthage was an independent colony of Phoenicians which
had won an empire in the western Mediterranean by its sea-power. It
held a great part of Spain, the whole of Sardinia, most of Sicily, and
many other islands. The