On October 1, 331 BC, two armies clashed on the plain of Gaugamela, deciding the fate of the ancient Near East. The Macedonian king Alexander III, known in history as Alexander the Great, defeated the Persian ruler Darius III and gained access to the capitals of the Achaemenid Empire.
Gaugamela is located in Mesopotamia, east of the Tigris River, in the region of modern-day Iraq. The battle is also known as the Battle of Arbela because of the nearby city, associated with modern-day Erbil. The Persian king chose open and prepared terrain, which allowed his cavalry and chariots to maneuver.
Alexander refuses to attack at night
The decisive clash came after two heavy defeats for Persia at the Granicus River in 334 BC and at Issa in 333 BC. After Issa, Darius III managed to retreat and gather a new, significantly larger army. However, Alexander had already gained combat experience and had disciplined infantry, cavalry, and commanders accustomed to acting in concert.
On the night before the battle, some of Alexander's generals proposed a surprise attack. According to the historian Arrian, the king refused, saying: „It would be a shame to steal the victory.“ Thus, the Macedonian army waited for daylight to confront the Persian forces in open battle.
The blow to the center decides the outcome
Darius III deployed his troops in such a way as to take advantage of his numerical superiority and the wide battlefield. The Persian army included cavalry from various parts of the empire, infantry, and war chariots. The Macedonians were outnumbered, but Alexander maintained the mobility of his formations and looked for a gap in the enemy line.
At the decisive moment, he led his cavalry towards the Persian center, where Darius was. The attack created a danger for the king and his headquarters. Darius left the battlefield, and his retreat contributed to the collapse of Persian resistance. Details of the movements of the ruler and his troops differ in ancient accounts, but a contemporary Babylonian astronomical diary also records Darius' defeat and the flight of his men.
Victory does not complete the conquest in a day
Gaugamela was a decisive military victory, but the Persian Empire did not completely disappear on the day of the battle. Alexander continued on to Babylon, which he entered in October 331 BC, and then captured Susa and Persepolis. The British Museum describes the victory at Gaugamela as the culmination of a series of battles, after which Alexander took control of Babylon and began to extend his control eastward.
Darius III retreated to the eastern regions of the state, but was unable to regain his power. In 330 BC, he was assassinated by his own cronies while Alexander pursued him. After Gaugamela, Alexander presented himself as the heir to the Persian royal power, and the conquered territories became the basis of a huge state stretching from Egypt and Asia Minor to Central Asia and India.
Therefore, the Battle of Gaugamela remained more than just a victory over an army. It shattered the political center of the Achaemenid Empire and changed the course of the history of the ancient world.
Sources: worldhistory.org, livius.org, britishmuseum.org, iranicaonline.org