It was made before the expedition started; and presumably its results were known before the fleet sailed from the Asian coast. #OBJECTIVE OF EXPEDITION OF 490.# Thus the Persian commanders knew what they had to expect; and, if Herodotus’ statements be correct, a large number of states had been detached from the possible defence. Then there was Hippias. His presence with the expedition served a double purpose. He was an outward and visible sign of the limitations of the Persian intentions. He was to be re-established as tyrant in Athens. But the Persian might expect more from him. His presence might detach Sparta from the defence. Was it not Sparta which had, not so many years before, called the Peloponnesian states together and proposed the forcible reinstatement of Hippias? Everything, in fact, points to the correctness of one of the views entertained by Herodotus, that this expedition was aimed against Athens and Eretria alone. It was in a sense the completion of the work done in the suppression of the revolt, and a precaution against the recurrence of such an outbreak. Not merely must the European Greeks be taught the danger of interfering in the affairs of the empire, but the subjugation of the interfering states must show the Ionians that in future they could not expect help from their free kinsmen beyond the seas. It is, however, impossible to suppose that the Persian design ended here, and that, had a footing been once won in Attica, the Persian Government would have contented itself with the punishment of that state, and then have withdrawn its troops. ◆H. vi. 96.◆ The action with regard to Naxos and the other Islands on the passage of the Ægean shows that Persia intended to acquire this most effective line of communication; in other words, that the second motive of this expedition was identical with that which had made Artaphernes the satrap so keen to take up the design of Aristagoras in 500 B.C., the desire to acquire a base in the Western Ægean against European Greece. The expedition was to be the preliminary step in larger schemes of conquest. It was in accord with Persian practice at this time that the command of the new venture should be entrusted to some other general than the leader in 492. ◆H. vi. 94.◆ Mardonios was deposed, says Herodotus, because he had mismanaged the previous expedition. That, as has been seen, had not been the case; and the change of leadership seems to have been simply an instance of the regular policy of Darius with regard to high military command. The new generals were Datis, a Mede, and Artaphernes, the son of the great satrap of the same name, and nephew of Darius. From Susa the army was conducted to the Aleian plain in Cilicia, where the fleet and transports met it. On these vessels it was embarked and sailed to Ionia.