Origins
Alexander was born in July 356 BC at Pella, the capital of the kingdom of Macedon, to King Philip II and his queen Olympias. His childhood was unusual by Greek standards. From age 13 to 16 he was tutored by Aristotle at the royal retreat of Mieza; the curriculum covered philosophy, medicine, scientific reasoning, and a substantial reading of Homer’s Iliad, which Alexander would reportedly carry with him on campaign.
Philip II had spent twenty years reorganizing the Macedonian state and military, producing the most effective army in the Greek world: the combined-arms force of long-spear (sarissa) infantry phalanx, heavy Companion cavalry, and integrated specialist arms that would conquer the Persian Empire. Philip was assassinated in October 336 BC by a bodyguard whose motives remain unclear (the leading theories implicate Olympias, a Persian-funded plot, or a personal grievance). Alexander was 20. The succession was contested but Alexander secured the throne within months.
The Persian campaign
Alexander invaded Asia in spring 334 BC at the head of approximately 40,000 troops. The Achaemenid Persian Empire under Darius III was larger, wealthier, and could field substantially more men, but its military system — relying on heavy mercenary infantry, light archery, and chariot-based tactics — was no longer competitive with the Macedonian phalanx-and-cavalry combination.
The campaign was won in four major battles. Granicus (May 334 BC) destroyed the satrapal armies of western Anatolia and opened Asia Minor. Issus (November 333 BC) destroyed Darius’s first imperial army in the Levantine corridor; Darius’s family was captured but Darius himself escaped. Gaugamela (October 331 BC), on the plain northeast of Arbela in modern Iraq, destroyed Darius’s second and larger imperial army and ended the Achaemenid Empire as a political reality. Babylon and Susa surrendered without resistance; Persepolis was burned (an event whose deliberateness is still debated). Darius was murdered by his own satrap Bessus in summer 330 BC.
Alexander continued east for another five years, campaigning in modern Iran, Afghanistan, and Central Asia, suppressing local revolts, and pushing across the Hindu Kush into the Punjab. The eastern campaign culminated in the battle of the Hydaspes (May 326 BC) against the Indian king Porus. Alexander’s army, exhausted by eight years of continuous campaigning, mutinied at the Hyphasis river in summer 326 and refused to march further east. Alexander returned west by river and overland through the Gedrosian desert (a march that cost the army more casualties than any of the battles).
Death and consequences
Alexander died at Babylon on 10 or 11 June 323 BC after a ten-day illness. He was 32. The cause is disputed — modern medical opinion favours typhoid fever or West Nile encephalitis; ancient sources also describe symptoms consistent with malaria or alcoholic complications; a poisoning theory has had defenders since antiquity. There was no acknowledged successor. His generals — the Diadochi (“Successors”) — fought a forty-year series of wars that partitioned the empire into the major Hellenistic states: Ptolemaic Egypt, Seleucid Asia, and Antigonid Macedon. None of them held together for long.
Hellenistic legacy
Alexander’s conquests produced the Hellenistic civilization that dominated the eastern Mediterranean and Near East for three centuries. Greek language, urban planning, sculptural style, philosophical schools, and scientific institutions spread from the Aegean to the Hindu Kush. The cities he founded — most prominently Alexandria in Egypt, site of the Library of Alexandria and the Pharos lighthouse — became the leading intellectual centres of the Hellenistic world.
His Macedonian Greek successor kingdoms ruled most of the territory Alexander had conquered until the Roman conquests of the 2nd and 1st centuries BC absorbed them one by one, ending with the death of Cleopatra VII of Egypt in 30 BC — the last reigning member of the Ptolemaic dynasty founded by Alexander’s general Ptolemy. The Hellenistic period, conventionally dated 323 BC to 30 BC, is one of the most productive and territorially extensive periods of Greek culture in history; it begins and ends with the death of an Alexander-line monarch.
Alexander himself is the only individual in classical antiquity whose tomb location was a major political-religious question for centuries. The body was hijacked by Ptolemy and brought to Alexandria, where it was an attraction for Roman emperors visiting Egypt (including Augustus, who reportedly broke Alexander’s nose by accident while paying respects). The tomb’s exact location was lost in late antiquity and has never been recovered.