his son, Alexander III, who had to put down several revolts in the Balkans and Greece first to reassert Macedonian authority. This distracted him from the operations in Asia Minor. Meanwhile, Darius III had become the new Great King of the Achaemenid Empire, around the autumn of 336 BC. He managed to stabilize the empire and started a counter-offensive against the Macedonian expeditionary force. Darius prioritized the suppression of the Egyptian revolt, which probably took place from the end of 336 BC to February 335 BC. When this was done he sent Memnon of Rhodes to Asia Minor at the head of a force of Greek mercenaries, who were infantry fighting as hoplites. Memnon defeated a Macedonian force at either Magnesia ad Sipylum or Magnesia on the Maeander, probably in early spring 335 BC. Later that year another Macedonian force was defeated by a Persian army in the Troad, possibly under the command of one or more Persian satraps. By the end of 335 BC most of the Greek cities had been restored to Persian control and the expeditionary force retained only Abydus and perhaps Rhoeteum. Prelude Once Alexander had defeated the rebellions in the Balkans and Greece, he marched his army to the Hellespont in early spring 334 BC. His army numbered c. 32,000 infantry and c. 5,000 cavalry. He arrived at Sestus twenty days later, where he split his army for the crossing of the Hellespont. The main part of the army was transported from Sestus to Abydus in Asia Minor, while Alexander crossed with the remainder of the infantry from Elaeus, landing near Cape Sigeum. After visiting Ilium, he passed Arisba, Percote, Lampsacus, Colonae and Hermotus. Darius would have been informed about Alexander's movements for some time, maybe as early as the invasion force had left Macedon. This did not alarm the Great King yet, who left the defense of Asia Minor to his satraps there. The reasons for this may have been that Alexander had not proven himself as a commander abroad yet and that the Macedonian expeditionary force had been pushed back without much difficulty the previous year. The Persian satraps and commanders were encamped near Zeleia with their army when they were informed of Alexander's crossing. The army was led by Arsites, the satrap of Hellespontine Phrygia, Spithridates, satrap of Lydia and Ionia, Arsames, satrap of Cilicia, Rheomithres, Petenes, Niphates and Memnon of Rhodes.