After his victory at the Battle of Chaeronea (338 BC), Philip II began the work of establishing himself as "hēgemṓn" () of a league which according to Diodorus was to wage a campaign against the Persians for the sundry grievances Greece suffered in 480 and free the Greek cities of the western coast and islands from Achaemenid rule. In 336 he sent Parmenion, with Amyntas, Andromenes and Attalus, and an army of 10,000 men into Anatolia to make preparations for an invasion. 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 the mercenary Memnon of Rhodes.