In twenty years, Philip transformed Macedon from a geographically large but politically and culturally insignificant state into the unquestioned hegemon of the Greek world. Prior to his ascendancy in 359 BC, Macedon was a well-established kingdom but seen by the Greeks to the south as inferior and culturally backward. Determined to change this reality, only four years into his reign Philip besieged Methone, an insignificant Greek city but one that was a colony of Athens. Philip’s moves aroused the Greece’s most important state and most powerful navy to act against him.


 
Athens sent a fleet in 354, but in a stunning sign of the shifting power balance they were crushed by Philip’s relatively untested forces. Emboldened, he then spent a decade picking off the weaker city-states of northern Greece and certain rogue tribes of the Balkans before turning to the big prizes further south: Athens, Sparta, and Thebes. Philip sent an emissary to the defiant Spartans, warning “if I invade, I shall turn you out,” to which the Spartans famously replied just one word: “if.” But Philip did soon after invade Sparta, and not only defeated the Spartan army on the field but, as he had declared, laid waste to the city and countryside. The two great remaining powers of Greece, Athens and Thebes, had been bitter rivals for decades, but now seeing the Macedonian threat to be too strong, they entered an alliance.
 
The Macedonian army, its left wing commanded by an 18-year old Alexander the Great, met the Athenian-Theban forces at Chaeronea on August 2, 338 BC. The last great battle of the Classical Greek era was fought under blistering sun and between armies of about equal size. But innovative Macedonian tactics, particularly the phalanx, proved superior, as the Greeks lost ten times as many men. Philip and the defeated Greeks formed the League of Corinth, a union with the objective of invading the Persian Empire to the east. Philip’s untimely assassination just two years later in 336 BC meant the responsibility of marching east fell to his son Alexander; the rest is history.