"After successfully annexing Thessaly and Thrace, Philip was widely acknowledged as the natural leader of a Hellenic alliance. The venerable Isocrates saw Philip as the man that Greece needed to deal with a chronic demographic problem that menaced its future. He argued that Greece was plagued by overpopulation, which produced large numbers of men suitable for military service who wandered about, without loyalty to any city, selling their services to anyone who could pay for them and thereby posing a constant menace to the stability of the country. What was needed, he suggested, was a new country that might be colonized by Greece's surplus population. This new land would have to be conquered from Persia, and Philip of Macedon, who was already successfully challenging the Persians in a contest for control of the European shores of the Hellespont, was clearly the only one who might be able to annex all Anatolia to the Hellenic world."