The Greeks soon began their march down the coast. The satraps of the neighboring provinces had in the meantime gathered together all the troops available in the Propontis and had joined the army of Memnon. From the statements made in contemporary sources, it is not possible to gather the numerical strength of the army which now opposed Alexander’s advance; it is certain, however, that in infantry the Persians were weaker than the Greeks, while it is probable that they were also outnumbered in cavalry. They were certainly aware of their weakness, because Memnon advised against a stand-up battle, suggesting instead that they should retire into the interior, wasting the country as they went, and so hinder the rapidity of the enemy’s march until their own fleet appeared; then the war could be carried into Greece and Alexander forced to retreat. But this prudent strategy was not acceptable to the Persian satraps, who preferred active measures that seemed to offer a chance of preventing Alexander from getting a firm foothold in Persian territory. They prepared to offer battle by taking up a position on the river Granicus, a stream flowing down from the northern slope of Mt. Ida to the Propontis. It seems as if the Persians, conscious of their weakness, selected a battlefield where their enemies, with a river in front of them, would find it a matter of some difficulty to attack. They may have supposed that Alexander would hesitate to advance under such unfavorable conditions. The Macedonian army was so disposed that the heavy-armed infantry held the center while the wings were formed by the cavalry and the bowmen. Alexander himself was with the picked Macedonian cavalry on the right wing; next him were arranged the hypaspists, extending towards the middle. This wing, comprising cavalry, bowmen, and heavy-armed troops, appears to have crossed the river first and to have put to flight the Persian cavalry. That the Persians used horsemen here and not bowmen seems strange. Cavalry were of little use in preventing an advance up the steep slope from the stream.