But this fair dawn was soon overcast.

As the fleet was rounding Athos a terrible tempest arose which, destroyed 300 triremes and more than 20,000 men, some of whom were devoured by sea-monsters, while the remainder perished by drowning.

On shore, a night attack of the Brygi, a Thracian tribe dwelling in the tract between the Strymon and the Axius, brought disaster upon the land force, numbers of which were slain, while Mardonius himself received a wound.
This disgrace, indeed, was retrieved by subsequent operations, which forced the Brygi to make their submission; but the expedition found itself in no condition to advance further, and Mardonius retreated into Asia.
Darius, however, did not allow failure to turn him from his purpose.
The attack of Mardonius was followed within two years by the well-known expedition under Datis (B.C.

490), which, avoiding the dangers of Athos, sailed direct to its object, crossing the Egean by the line of the Cyclades, and falling upon Eretria and Attica.

Eretria's punishment warned the Athenians to resist to the uttermost; and the skill of Miltiades, backed by the valor of his countrymen, gave to Athens the great victory of Marathon.