Gaugamela, Battle of

Decisive defeat in 331 BC of the Persians under Darius III (ruled about 380–330 BC) by the Macedonian king Alexander the Great. Alexander's tactical superiority enabled his troops to defeat the massed Persian army and the defeated Darius fled. He was later killed by his own troops, effectively giving Alexander the whole of Asia Minor.

The battle took place at the ancient town of Gaugamela, on the east bank of the River Tigris in Upper Mesopotamia, in the Persian satrapy (province) of Adiabene, about 80 km/50 mi northeast of Nineveh (now Al Mawsil, Iraq).

Alexander, at the head of a force of about 47,000 Macedonians and Greeks, was confronted by about 120,000 Persians under Darius. He personally led his right wing in an attack against the junction of the Persian centre and left wing, separating them and then taking the Persian centre in its flank. The Macedonian left was also pressing the Persians hard; Darius' forces gave way between the two Macedonian wings and a rout ensued with Darius forced to flee. Alexander's strong cavalry pursued them hard, with considerable slaughter, before the last of the Persians managed to escape.