The main task, however, which Mardonios was commissioned to perform lay in Europe. Herodotus’ description of the design of the expedition is remarkable.
H. vi. 43, 44.
“Having crossed the Hellespont in ships, they proceeded on their march against Eretria and Athens. These places were the pretended objects of the expedition. But as they intended to subdue as many of the Greek cities as possible, they in the first place reduced the Thasians with their fleet without resistance, and then with the army added the Macedonians to the number of those in servitude. All the tribes on the near side of Macedonia had been already reduced.”
It is noteworthy that all this had been achieved before serious disaster fell on the expedition. It was after the reduction of Macedonia,—a conquest which the history of subsequent years shows to have been genuine and complete,—that the fleet, coming from Thasos and Akanthos, was caught in a storm off Mount Athos, the easternmost of the promontories of the peninsula of Chalkidike. The reported loss, says Herodotus, was 300 ships and 20,000 men, his language implying that he was disposed to regard the number as exaggerated.
Another disaster of a minor character befel the land forces. They were attacked at night by a tribe in Macedonia called the Brygi; Mardonios himself was wounded, and the Persian losses are said to have been considerable; but Herodotus expressly adds that—
H. vi. 45.
“Not even the Brygi escaped slavery at the hands of the Persians; for Mardonios did not leave the region until he had reduced them. After subduing them, he took his expedition back [to Asia], for the army had met with disaster at the hands of the Brygi, and the fleet had suffered terribly off Athos. So the expedition went back to Asia, after meeting with disgraceful reverses.”
The two main questions with regard to this expedition are—
(1) As to its intent;
(2) As to its practical results.