During the first half of the fourth century B.C., Greek poleis, or city-states, remained autonomous. As each polis tended to its own interests, frequent disputes and temporary alliances between rival factions resulted. In 360 B.C., an extraordinary individual, Philip II of Macedonia (northern Greece), came to power. In less than a decade, he had defeated most of Macedonia’s neighboring enemies: the Illyrians and the Paionians to the west and northwest, and the Thracians to the north and northeast. Phillip II instituted far-reaching reforms at home and abroad. Innovations—improved catapults and siege machinery, as well as a new kind of infantry in which each soldier was equipped with an enormous pike known as a sarissa—placed his armies at the forefront of military technology. In 338 B.C., at the pivotal battle of Chaeronea in Boeotia, Philip II completed what was to be the last phase of his domination when he became the undisputed ruler of Greece. His plans for war against Asia were cut short when he was assassinated in 336 B.C. Excavations of the royal tombs at Vergina in northern Greece give a glimpse of the vibrant wall paintings and rich decorative arts produced for the Macedonian royal court (37.11.8-.17), which had become the leading center of Greek culture.

The reign of Alexander the Great (336–323 B.C.) would change the face of Europe and Asia forever (10.132.1; 55.11.11). As crown prince, he received the finest education in the Macedonian court under his celebrated tutor Aristotle. At the age of twenty, already a charismatic and decisive leader, Alexander quickly harnessed the Macedonian forces that his father’s reforms had made into the premier military power in the region. In 334 B.C., he led a grand army across the Hellespont in Asia. With some 43,000 infantry and 5,500 cavalry, it was the most formidable military expedition ever to leave Greece. The first to reach Asiatic soil, Alexander leapt ashore, cast a spear into the land, and dramatically claimed the continent as “spear won.” In a remarkable campaign that lasted eleven years, he went on to fulfill his claim and more by conquering the Persian empire of western Asia and Egypt, and by continuing into Central Asia as far as the Indus Valley. In the end, he was defeated by his own army, which insisted on returning to Greece. On the way back, he died of fever in Babylon at the age of thirty-three. All the lands that he had conquered were divided up among his generals (52.127.4), and it was these political divisions that comprised the many kingdoms of the Hellenistic period (323–31 B.C.).