Macedonia's military capabilities". Defense of the Achaemenid Empire Campaigns against Philip II When Mentor died in c. 340 BC, Memnon married his widow Barsine. In 339 BC, Memnon helped to defend Byzantium against an assault by Philip II. In 336 BC Philip II sent Parmenion, with Amyntas, Andromenes and Attalus, and an army of 10,000 men into Anatolia to make preparations for an invasion to free the Greeks living on the western coast and islands from Achaemenid rule. At first, all went well. The Greek cities on the western coast of Anatolia revolted until the news arrived that Philip had been murdered and had been succeeded by his young son Alexander. The Macedonians were demoralized by Philip's death and were subsequently defeated near Magnesia by the Achaemenids under the command of Memnon of Rhodes. Campaigns against Alexander the Great When Philip's son Alexander invaded the Persian Achaemenid Empire in 334 BC, Memnon, aware of the political issues the Macedonians dealt with, urged king Darius III (336–330 BC) to orchestrate a rebellion in Greece and he advised the Persian satraps to lay waste to the land that Alexander would have to pass, depriving his army of food and supplies. This would make it harder for Alexander and his army to survive on their long journey before the battle. The satraps did not trust Memnon because of his ethnicity, and did not ravage their territories. Initially hesitant, Darius made Memnon the commander of the western satrapies (provinces) after the defeat at the Battle of Granicus. During the defense of Halicarnassus, Memnon was the leading commander, and nearly defeated Alexander's attack. He then started using the empire's naval superiority against Alexander and started negotiations with Sparta in order to take the war to mainland Greece. He began a campaign to capture the Aegean islands using the Persian fleet and led a direct assault on Macedonia, while Alexander was resting at Phaselis. Memnon managed to capture the island of Chios and most of Lesbos. Demosthenes, after hearing of Memnon's successes, began to prepare Athens for a revolt against Alexander, along with other Greek cities, while Sparta began to prepare for war. By a stroke of fortune for Alexander, Memnon died during the siege of Mytilene, after transferring command to his nephew, Pharnabazus. Memnon's widow Barsine, according to Plutarch and Justin, later became Alexander's mistress and allegedly bore him a son, Heracles. After Alexander's death,