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 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.
The oblique advance
Badly outnumbered, Alexander did not attack head on. He advanced his line at an angle, edging to the right, 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 again. Then Alexander struck. At the head of his elite Companion cavalry, formed into a wedge, he drove straight through the gap 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 fell 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.