Who was Alexander the Great? The king who conquered Persia

Alexander the Great (356–323 BC) was king of Macedon, a kingdom in the north of Greece, who in eleven years conquered the Persian Empire, then the largest state in the world, and led his army as far as the Indus valley in what is now Pakistan. He never lost a pitched battle. He died in Babylon in June 323 BC, aged 32, and his generals carved his empire into kingdoms that spread Greek language and culture across the Middle East.

In short

• Alexander inherited a superb army and a plan to invade Persia from his father, Philip II, and carried it out further than anyone imagined.
• He beat the Persian king Darius III in three great battles, at the Granicus, Issus and Gaugamela, then fought on for seven more years into Central Asia and India.
• Almost everything known about him was written by Greek and Roman authors three to five centuries after he died, so the record and the legend are hard to pull apart.

Where did Alexander come from?

He was born in July 356 BC at Pella, the Macedonian capital, the son of King Philip II and Olympias, a princess from Epirus. Philip had turned Macedon from a backward kingdom into the strongest power in Greece, with a professional army built around the phalanx, a block of infantry armed with pikes about 5 to 6 meters long, and a heavy cavalry called the Companions. From about 343 BC, Philip hired the philosopher Aristotle to teach the teenage Alexander at Mieza for around three years. At 18, Alexander commanded the cavalry wing at Chaeronea in 338 BC, the battle that made Philip master of Greece.

Philip was planning to invade the Persian Empire when he was murdered in 336 BC, and Alexander, at 20, became king. He secured the throne by killing rivals, crushed revolts in the north, and when the Greek city of Thebes rebelled in 335 BC, he destroyed it, sparing only its temples and, by tradition, the house of the poet Pindar. The other Greek cities got the message.

How did he conquer the Persian Empire?

The Persian, or Achaemenid, Empire stretched from Egypt and the Aegean to Central Asia. Its king, Darius III, could raise far larger armies, but Alexander's force was better trained and better led, and he struck fast at the center of the enemy line, usually at the head of the Companion cavalry himself. The decisive pattern of his battles was the same: hold the line with the phalanx, then break through with cavalry at the point where the enemy king stood.

When	Where	What happened
Spring 334 BC	Hellespont and Troy	Crosses into Asia with an army usually estimated at 40,000 to 55,000; honors Achilles at Troy
334 BC	River Granicus, northwest Turkey	Defeats the Persian governors' army; western Asia Minor opens to him
November 333 BC	Issus, southern Turkey	Defeats Darius, who flees; his mother, wife and daughters are captured
332 BC	Tyre and Gaza	Takes the island city of Tyre after a seven-month siege, then Gaza
332–331 BC	Egypt	Welcomed as pharaoh; founds Alexandria; visits the oracle of Ammon at Siwa
1 October 331 BC	Gaugamela, northern Iraq	Defeats Darius's largest army; the empire's heartland falls
331–330 BC	Babylon, Susa, Persepolis	Takes the Persian capitals and treasuries; the palace at Persepolis burns
330 BC	Northern Iran	Darius is killed by his own nobles while fleeing
329–327 BC	Bactria and Sogdiana, Afghanistan and Uzbekistan	Hard guerrilla war; marries Roxana, a Sogdian noble's daughter
326 BC	River Hydaspes, Pakistan	Defeats King Porus and his war elephants
326 BC	River Hyphasis, now the Beas	His exhausted army refuses to go farther east
325 BC	Gedrosian desert, Iran and Pakistan	A disastrous march back west; many die of thirst
10 or 11 June 323 BC	Babylon	Dies after about twelve days of fever

The conquest of the empire was mostly done after Gaugamela. The last seven years were something else: a war against local leaders in Central Asia, and a push into India that went beyond anything the Persians had ruled for long. His troops had marched thousands of kilometers, and at the Hyphasis they would go no farther.

How did he rule what he won?

Alexander kept much of the Persian system: its provinces, called satrapies, its tax machinery and often its Persian governors. He adopted parts of Persian royal dress and court ritual, and in 324 BC at Susa he married two Persian royal women and had dozens of his senior officers marry Persian and other noble brides in a mass ceremony. Many Macedonians resented this, and his court grew dangerous. He executed his general Parmenion and Parmenion's son on suspicion of plotting, and in a drunken quarrel in 328 BC killed his friend Cleitus with a spear.

He founded or refounded many cities, a number of them named Alexandria. The greatest, in Egypt, became the largest city of the Greek world, with its famous library.

How did he die, and what came after?

He fell ill after a long night of drinking in Babylon and died about twelve days later. The cause is unknown. Ancient writers reported a rumor of poison and mostly doubted it; modern suggestions include malaria, typhoid fever, the effects of heavy drinking and wounds, and rarer diseases, and none can be proven from the surviving descriptions.

He left no adult heir. His generals, known as the Successors, fought each other for forty years, and his son by Roxana was murdered as a boy. Three main kingdoms emerged: the Ptolemies in Egypt, the Seleucids in Syria, Mesopotamia and Iran, and the Antigonids in Macedon. The centuries that followed are called the Hellenistic period, when Greek was the language of government and learning from the Mediterranean to Afghanistan. It ended in 30 BC, when Cleopatra, the last ruler of the Ptolemaic dynasty, died and Egypt fell to Rome, whose generals and emperors measured themselves against Alexander.

How much of the story is true?

Less than the films suggest, and more than nothing. The men who marched with him wrote histories, including his general Ptolemy, later king of Egypt, but all are lost. What survives was written long after, by authors who used them:

Author	When	Roughly how long after Alexander
Diodorus of Sicily	1st century BC	about 300 years
Quintus Curtius Rufus	1st century AD	about 350 years
Plutarch, Life of Alexander	about AD 100	about 400 years
Arrian, Anabasis of Alexander	2nd century AD	about 450 years

Arrian, the source modern historians trust most, based his account on Ptolemy and another companion, Aristobulus, as Livius's survey of his sources explains. Arrian himself said he trusted those two because both had been eyewitnesses. A few contemporary records do survive, such as Babylonian astronomical diaries that note the battle of Gaugamela and the day of his death. The famous stories, such as cutting the Gordian knot, taming the horse Bucephalus or weeping that there were no worlds left to conquer, come from these later authors or from the Alexander Romance, a book of legends that grew for centuries. Alexander himself worked at his legend: he carried a copy of Homer's Iliad and cast himself as a new Achilles, the hero of a war whose own reality is still debated.

Still argued

Historians disagree about almost everything beyond the battles. Some see a visionary who wanted to join Greeks and Persians in one realm; others, a brilliant and increasingly paranoid conqueror whose campaigns killed many thousands of people, including the populations of cities that resisted. His private life is argued too: his deep bond with his friend Hephaestion is described in the sources, but whether it was sexual cannot be settled from them. Modern judgments of him say as much about the eras that made them as about Alexander, which is one reason history is rewritten in every generation.

Check yourself

• What did Alexander inherit from his father that made the conquest possible?
• Why are the battles of Issus and Gaugamela seen as the turning points, and what did he spend the next seven years doing?
• Why is it hard to separate fact from legend in Alexander's life, and which kinds of evidence are closest to the events?

Sources

• Alexander the Great — Joshua J. Mark, World History Encyclopedia, 2013
• Alexander the Great — Jona Lendering, Livius.org
• Alexander the Great: Arrian's sources — Jona Lendering, Livius.org
• Life of Alexander, in Parallel Lives — Plutarch, translated by Bernadotte Perrin, LacusCurtius, University of Chicago
• Ptolemaic Dynasty — Arienne King, World History Encyclopedia, 2024
• Alexander the Great — Wikipedia