yet submitted to the Persian power. He
ordered the fleet to double the promontory of Mount Athos, and join the
land forces at the head of the gulf of Therma; but one of the
hurricanes which frequently blow off this dangerous coast overtook the
Persian fleet, destroyed 300 vessels and drowned or dashed upon the
rocks 20,000 men. Meantime the land forces of Mardonius had suffered
so much from an attack made upon them by a Thracian tribe, that he
could not proceed farther. He led his army back across the Hellespont,
and returned to the Persian court covered with shame and grief (B.C.
492).

The failure of this expedition did not shake the resolution of Darius.
He began to make preparations for another attempt on a still larger
scale, and meantime sent heralds to most of the Grecian states to
demand from each earth and water as the symbol of submission. Such
terror had the Persians inspired by their recent conquest of Ionia,
that a large number of the Grecian cities at once complied with the
demand; but the Athenians cast the herald into a deep pit, and the
Spartans threw him into a well bidding him take earth and water from
thence.

In the spring of B.C. 490 a large army and fleet were assembled in
Cilicia, and the command was given to Datis, a Median, and Artaphernes,
son of the satrap of Sardis of that name. Warned by the recent
disaster of Mardonius in doubling the promontory of Mount Athos, they
resolved to sail straight across the AEgean to Euboea, subduing on
their way the Cyclades. These islands yielded a ready submission; and
it was not till Datis and Artaphernes reached Euboea that they
encountered any resistance. Eretria defended itself gallantly for six
days, and repulsed the Persians with loss; but on the seventh the gates
were opened to the besiegers by the treachery of two of its leading
citizens. The city was razed to the ground, and the inhabitants were
put in chains. From Eretria the Persians crossed over to Attica, and
landed on the ever memorable plain of Marathon, a spot which had been
pointed out to them by the despot Hippias, who accompanied the army.

As soon as the news of the fall of Eretria reached Athens, a courier
had been sent to Sparta to solicit assistance. This was promised; but
the superstition of the Spartans prevented them from setting out
immediately, since it wanted a few days to the full moon, and it was
contrary to their religious customs to commence a march during this
in