A King at 20
Alexander III of Macedon was born in 356BC to King Philip II and educated by Aristotle — widely considered the greatest mind of the ancient world. He learned philosophy, medicine, science and rhetoric. But Alexander was not interested in scholarship for its own sake. By 16 he was acting as regent while his father campaigned, by 18 he was leading cavalry at the Battle of Chaeronea, and at 20 — when Philip II was assassinated — he moved swiftly to consolidate power, eliminating rivals and crushing a Theban revolt (razing the city to demonstrate the cost of resistance).
The Persian Campaign
In 334BC Alexander crossed into Persian territory with an army of approximately 47,000 men, taking on an empire that, on paper, dwarfed his own — a state stretching from Egypt to the edge of India, governed through provincial administrators and a sophisticated communications network built over two centuries. What followed was a decade of relentless campaigning. He never lost a battle. At Gaugamela in 331BC he defeated a Persian force estimated at over 100,000. Egypt fell without resistance — the Egyptians welcomed him as a liberator and declared him a god. Persepolis, the Persian royal capital, was burned.
He pushed east through Afghanistan into India, defeating King Porus at the Battle of the Hydaspes in 326 BC — and then, at the Hyphasis river shortly after, his army simply stopped. Eleven years into the campaign, having marched thousands of miles from home, his men refused to go further east into what seemed like endless unknown territory. Alexander, reportedly in tears, agreed to turn back. It remains one of history's clearest illustrations of a fundamental truth about even the most successful conquests: an empire cannot extend further than the people fighting for it are willing to go.
The Secret of Alexander's Military Success
Alexander combined the Macedonian phalanx — armed with the 18-foot sarissa pike — with the Companion cavalry, which he personally led in decisive charges. Crucially, he always led from the front and was wounded multiple times. His soldiers would follow him anywhere because they had seen him bleed alongside them. This personal leadership style, combined with superior tactical flexibility, consistently overcame numerically larger forces.
Death in Babylon
In 323BC, in Babylon, Alexander attended a banquet and fell ill. Over twelve days he deteriorated — fever, loss of speech, progressive paralysis. He was dead at 32. The cause remains disputed: poison (suggested by ancient sources), typhoid fever, bacterial infection from contaminated wine, and Guillain-Barré syndrome (which would explain the reported six days with no signs of decay — he may have been in a coma) have all been proposed. No consensus exists.
His generals immediately began fighting over the empire. When asked who should inherit, Alexander reportedly said "the strongest." Within a generation, the empire had fractured into rival successor kingdoms carved up by his own former commanders — the Ptolemaic kingdom in Egypt, the Seleucid empire across the former Persian heartland, the Antigonid kingdom in Macedonia itself. The unified empire he had built in a decade was gone within a generation — a reminder that systems built around a single irreplaceable individual are always fragile. See our article on the Fall of Rome for another perspective on imperial fragility.
Yet Alexander's most durable legacy was cultural rather than political, and it far outlasted any of his generals' kingdoms. The Hellenistic world he created — Greek language, art, and philosophy spreading across the former Persian Empire and blending with local traditions — shaped the trajectory of Western civilisation for centuries afterward. The New Testament was written in Greek. The great library at Alexandria was a direct product of the Hellenistic intellectual culture his conquests set in motion. Empires built by force rarely survive their founder for long. What Alexander built culturally proved far more durable than what he built politically.
"I am not afraid of an army of lions led by a sheep; I am afraid of an army of sheep led by a lion." — Attributed to Alexander the Great
Frequently Asked Questions
How did Alexander the Great die?
Alexander the Great died in Babylon on 11 June 323 BC, aged 32. The cause of his death remains debated — theories include typhoid fever complicated by other illness, alcohol poisoning, or assassination by poison. He fell ill after a banquet and deteriorated over twelve days before dying. He left no clear successor.
Was Alexander the Great actually great?
Alexander's greatness is genuinely contested. He never lost a battle, conquered the largest empire the ancient world had seen, and spread Greek culture across three continents. However he also massacred civilian populations, executed close friends in rages, and his empire collapsed almost immediately after his death. His greatness depends entirely on which values you apply.
How big was Alexander the Great's empire?
At its peak Alexander's empire stretched approximately 5.2 million square kilometres — from Greece in the west to modern-day Pakistan in the east, encompassing modern Greece, Turkey, Egypt, Israel, Iran, Afghanistan and parts of India. He conquered this territory in just thirteen years of campaigning.
Who was Alexander the Great's teacher?
Alexander was tutored from age 13 by the philosopher Aristotle, one of the greatest intellects of the ancient world. Aristotle taught him philosophy, medicine, science and literature. Alexander reportedly kept a copy of Homer's Iliad annotated by Aristotle under his pillow alongside a dagger throughout his campaigns.
Did Alexander the Great conquer India?
Alexander reached the northwestern regions of the Indian subcontinent — modern-day Pakistan — in 326 BC, defeating King Porus at the Battle of the Hydaspes. However his troops refused to march further east into the Indian interior. Alexander was forced to turn back, and India remained largely unconquered by his forces.
A Note From The Editor
Alexander fascinates me precisely because his legacy is so impossible to untangle. He spread Greek culture across three continents and laid the foundations for centuries of intellectual exchange. He also massacred cities, executed friends in rages, and drove his men to the edge of mutiny pursuing a vision only he could see. Was he great? By the standards of his own time, unquestionably. By ours, far more complicated. The title has always said more about what we choose to celebrate than about the man himself.
The full picture is more complex than any short article can cover.
Would Alexander's empire have survived his death if he had lived another decade — or was its fragmentation structurally inevitable?