Philip gained his military education under Epaminondas of Thebes, where he was a royal hostage for three years. There he learned the value of coordinating cavalry with infantry in battle. He also learned a good deal about how Greek politics worked. His father died young, and Philip became king at age 25 in the year 359.
Philip inherited a kingdom that was historically divided between towns and farmers in the lowlands, and powerful nobles in the hills. He eliminated his rivals with brutal efficiency, subdued all rebellions, and managed to unite all Macedonia under his leadership.
He was a masterful politician, playing one faction off against another. He was fortunate in that gold had been discovered recently under Mt. Pangaeus, which was in his realm (imagine what would happen if the U.S. suddenly discovered vast oil reserves that could be brought into production within a matter of months). And he was able to lead his nobles to a string of foreign victories.
Victory came not least because Philip created a new type of army, a standing army of soldiers who served year-round. When not at war, the Macedonian army was barracked at state expense and underwent sophisticated training while in quarters. The Macedonian soldier was thus far better trained than any other in the world and much better equipped.
Philip borrowed and further developed the tactic of combining cavalry with infantry. And he invented the famed Macedonian phalanx, about which more later.
