Alexander the Great won a decisive victory at Gaugamela on 1 October 331 BC1, defeating the far larger Persian army of Darius III on ground the enemy had chosen in what is now northern Iraq. The victory broke the Persian Empire and made Alexander master of the known world.
On a wide plain in what is now northern Iraq, a young Macedonian king faced the full might of the Persian Empire on ground his enemy had chosen and prepared. By the end of the day at Gaugamela, that empire was broken, and Alexander the Great had made himself master of the known world.
The battle from both sides
Two perspectivesAlexander came to Gaugamela to end Darius and win the Persian empire outright, though the Persians had chosen and levelled the ground for their chariots and vast numbers. He drew his line up at an angle and edged rightward, stretching the Persian front until a gap opened in their centre. Into it he drove the wedge of his Companion cavalry, straight toward Darius himself. When the Great King fled, the heart went out of his army. The victory delivered Babylon, Susa and Persepolis and made Alexander master of the Persian world, though he would spend years and his own life pushing ever further east.
Darius met Alexander on open ground of his own choosing, levelled for scythed chariots and his huge, many-nationed host, determined to use numbers where the mountains had failed him at Issus. His chariots and cavalry pressed the Macedonian wings hard, and his horsemen broke through toward the baggage. But Alexander's oblique advance pulled the Persian line apart, and when the Companion wedge lunged at the royal position, Darius fled the field as he had at Issus. His flight unravelled the army and doomed the empire; within a few years Darius was dead at the hands of his own men and the Achaemenid realm was gone.
The second meeting
Alexander had already beaten the Persian king Darius III once, at Issus. Darius, determined not to lose again, gathered a vast army from across his empire and chose a broad, flat battlefield where his numbers, his cavalry and his scythed chariots could be used to the full. He even had the ground levelled for the chariots.2
The oblique advance
Badly outnumbered, Alexander did not attack head on. He advanced his line at an angle, edging to the right3, forcing the Persians to shift and stretch to match him. As Darius's line pulled sideways to keep from being outflanked, a gap began to open in it.
The wedge
The scythed chariots charged and were dealt with, the Macedonian ranks opening to let them pass and then closing again3. Then Alexander struck. At the head of his elite Companion cavalry, formed into a wedge, he drove straight through the gap4 in the Persian line and aimed himself directly at Darius.
The king flees
With Alexander bearing down on him, Darius fled the field. Once their king had run, the vast Persian army lost its heart and began to come apart, and what had been a battle became a rout.
An empire falls
Gaugamela decided the war. Babylon opened its gates, the Persian treasuries fell5 into Alexander's hands, and the empire that had once threatened Greece at Marathon and Salamis passed to a Macedonian king still in his twenties. It stands as one of the most complete battlefield victories in history.
The crisis on the left
While Alexander drove at the centre, his left wing under the veteran Parmenion was pressed hard by the Persian cavalry. A body of Persian and Indian horsemen poured through a gap that had opened in the Macedonian line and rode all the way to the baggage camp in the rear6. Alexander broke off his pursuit of Darius and turned his Companions back across the field, and the cavalry clash that followed, as the enemy horsemen tried to cut their way out, was the fiercest of the whole battle6. Only once it was over could the rout become complete.
The fall of the Persian Empire
Gaugamela broke the field army of the Achaemenid Empire. Alexander marched on to take Babylon, Susa and the great capital of Persepolis, seizing treasuries beyond counting. Darius fled east to Ecbatana and then into the mountains, but he never raised another army; in 330 BC he was murdered by one of his own satraps, Bessus7. The empire that had once threatened Greece now belonged to a Macedonian king still in his twenties.
See how it ranks in the greatest battles of antiquity.