At the same time, with a wisdom which we should scarcely have expected in an Oriental, he commissioned him, ere he quitted Asia, to depose the tyrants who bore rule in the Greek cities, and to allow the establishment of democracies in their stead.

Such a measure was excellently calculated to preserve the fidelity of the Hellenic population and to prevent any renewal of disturbance.

It gave ample employment to unquiet spirits by opening to them a career in their own states--and it removed the grievance which, more than anything else, had produced the recent rebellion.
Mardonius having effected this change proceeded into Europe.

He had a large land force and a powerful navy, and at first was successful both by land and sea.

The fleet took Thasos, an island valuable for its mines; and the army forced the Macedonians to exchange their position of semi-independence for that of full Persian subjects, liable to both tribute and military service.