Philip’s unification campaign came to a head in 338 BCE, at the Battle of Chaeronea in Boeotia. A coalition of Athens and Thebes—rivals now united in fear of Macedonian domination—faced Philip’s army, which included his 18-year-old son, Alexander.

The battle was decisive. Philip used classic Macedonian tactics, baiting the Greek right wing to advance and then breaking their line with a combined assault. Alexander led the cavalry that crushed the Sacred Band of Thebes—an event symbolic of the old guard falling to the new.

After Chaeronea, Philip formed the League of Corinth, uniting most of Greece under Macedonian leadership (Sparta notably refused to join). While the city-states retained nominal independence, their military and foreign policy were now controlled by Macedon. Greek independence, in the traditional sense, was effectively over.

Philip was now the master of Greece—and he set his eyes eastward, planning a pan-Hellenic war against Persia. But in 336 BCE, he was assassinated under mysterious circumstances, possibly orchestrated by his own family.

His son would carry out the dream—and surpass it.