How did Alexander the Great build his empire?
Alexander built his empire through military genius, the superior Macedonian army inherited from his father Philip II, decisive victories over the Persian Empire at Issus and Gaugamela, strategic use of local governance, the founding of Greek-style cities, and personal charisma that inspired fierce loyalty in his troops.
Alexander's empire was built through a combination of inherited advantages, personal genius, and relentless ambition. He began with the most formidable military machine in the Mediterranean world, refined it through tactical innovation, and deployed it with a speed and decisiveness that left his opponents unable to respond.
The foundation was the Macedonian army that Philip II had rebuilt. The phalanx — armed with the 5-meter sarissa pike — provided a nearly impenetrable infantry formation. The Companion cavalry, drawn from Macedonian nobility, provided shock force. Philip's combined-arms approach, integrating infantry, cavalry, and siege equipment, was unprecedented. Alexander inherited this army and added his own tactical genius.
Alexander's campaign began in 334 BCE with the crossing into Asia Minor. The Battle of the Granicus (334) secured the Anatolian coast. The Battle of Issus (333) defeated the Persian king Darius III and opened the Levant and Egypt. The decisive Battle of Gaugamela (331) — where Alexander used an oblique cavalry charge to shatter the Persian center — destroyed the Achaemenid Empire's military capacity.
But conquest required more than battlefield victories. Alexander showed remarkable political skill in managing his diverse domains. He adopted Persian court ceremonies and administrative practices, appointed local governors alongside Macedonian commanders, and encouraged his soldiers to marry local women. He founded dozens of cities — Alexandrias — as centers of Greek culture and administration.
Alexander's campaigns continued through Central Asia (329–327 BCE), where guerrilla resistance proved more challenging than set-piece battles, and into India (327–325 BCE), where his army finally refused to march further. His death in Babylon at age thirty-two in 323 BCE left an empire stretching from Greece to the Punjab — built in just eleven years of almost continuous campaigning.