XII. Meanwhile, the Persians suspended for that year all further hostilities against the Ionians. Artaphernes endeavoured to conciliate the subdued colonies by useful laws, impartial taxes, and benign recommendations to order and to peace. The next year, however, that satrap was recalled (B. C. 492), and Mardonius, a very young noble, the son-in-law of Darius, was appointed, at the head of a considerable naval and military force, to the administration of the affairs in that part of the Persian empire. Entering Ionia, he executed a novel, a daring, but no unstatesman-like stroke of policy. He removed all the Ionian tyrants, and everywhere restored republican forms of government; deeming, unquestionably, that he is the securest master of distant provinces who establishes among them the institutions which they best love. Then proceeding to the Hellespont, Mardonius collected his mighty fleets and powerful army, and passed through Europe towards the avowed objects of the Persian vengeance-- the cities of Eretria and Athens.
From the time that the Athenians had assisted the forces of Miletus and long in the destruction of Sardis, their offence had rankled in the bosom of Darius. Like most monarchs, he viewed as more heinous offenders the foreign abetters of rebellion, than the rebels themselves. Religion, no doubt, conspired to augment his indignation. In the conflagration of Sardis the temple of the great Persian deity had perished, and the inexpiated sacrilege made a duty of revenge. So keenly, indeed, did Darius resent the share that the remote Athenians had taken in the destruction of his Lydian capital, that, on receiving the intelligence, he is said to have called for his bow, and, shooting an arrow in the air, to have prayed for vengeance against the offenders; and three times every day, as he sat at table, his attendants were commanded to repeat to him, “Sir, remember the Athenians.”
XIII. But the design of Mardonius was not only directed against the Athenians and the state of Eretria, it extended also to the rest of Greece: preparations so vast were not meant to be wasted upon foes apparently insignificant, but rather to consolidate the Persian conquests on the Asiatic coasts, and to impress on the neighbouring continent of Europe adequate conceptions of the power of the great king. By sea, Mardonius subdued the islanders of Thasus, wealthy in its gold-mines; by land he added to the Persian dependances in Thrace and Macedonia. But losses, both by storm and battle, drove him back to Asia, and delayed for a season the deliberate and organized invasion of Greece.