Wars of Alexander the Great: Battle of Gaugamela

Alexander the Great
Public Domain

The Battle of Gaugamela was fought October 1, 331 BC during the Wars of Alexander the Great (335-323 BC).

Armies & Commanders



  • Darius III
  • Approx. 53,000-100,000 men


Having beaten the Persians at Issus in 333 BC, Alexander the Great moved to secure his hold on Syria, the Mediterranean coast, and Egypt. Having completed these efforts, he again looked east with the goal of toppling Darius III's Persian Empire. Marching into Syria, Alexander crossed the Euphrates and Tigris without opposition in 331. Desperate to halt the Macedonian advance, Darius scoured his empire for resources and men. Gathering them near Arbela, he chose a wide plain for the battlefield as he felt that it would facilitate the use of his chariots and elephants, as well as allow his greater numbers to bear.

Alexander's Plan

Advancing to within four miles of the Persian position, Alexander made camp and met with his commanders. In the course of the talks, Parmenion suggested that the army launch a night attack on the Persians as Darius' host outnumbered them. This was dismissed by Alexander as the plan of an ordinary general and he instead outlined an attack for the next day. His decision proved correct as Darius had anticipated a nighttime assault and kept his men awake through the night in anticipation. Moving out the next morning, Alexander arrived on the field and deployed his infantry into two phalanxes, one in front of the other.

Setting the Stage

On the right of the front phalanx was Alexander's Companion cavalry along with additional light infantry. To the left, Parmenion led additional cavalry and light infantry. Supporting the front lines were cavalry and light infantry units which were echeloned back at 45-degree angles. In the coming fight, Parmenion was to lead the left in a holding action while Alexander led the right in striking a battle-winning blow. Across the field, Darius deployed the bulk of his infantry in a long line, with his cavalry to the front.

In the center, he surrounded himself with his best cavalry along with the famed Immortals. Having chosen the ground to facilitate the use of his scythed chariots, he ordered these units placed at the front of the army. Command of the left flank was given to Bessus, while the right was assigned to Mazaeus. Due to the size of the Persian army, Alexander anticipated that Darius would be able to flank his men as they advanced. To counter this, orders were issued that the second Macedonian line should counter any flanking units as the situation dictated.

The Battle of Gaugamela

With his men in place, Alexander ordered an advance on the Persian line with his men moving obliquely to the right as they marched forward. As the Macedonians neared the enemy, he began extending his right with the goal of drawing the Persian cavalry in that direction and creating a gap between them and Darius' center. With the enemy bearing down, Darius attacked with his chariots. These raced forward but were defeated by Macedonian javelins, archers, and new infantry tactics designed to lessen their impact. The Persian elephants also had little effect as the massive animals moved to avoid the enemy spears.

As the lead phalanx engaged the Persian infantry, Alexander focused his attention on the far right. Here he began pulling men from his rearguard to continue the fight on the flank, while he disengaged his Companions and gathered other units to strike Darius' position. Advancing with his men forming a wedge, Alexander angled left toward the flank of Darius' center. Supported by peltasts (light infantry with slings and bows) which kept the Persian cavalry at bay, Alexander's cavalry rode down on the Persian line as a gap opened between Darius and Bessus' men.

Striking through the gap, the Macedonians shattered Darius' royal guard and adjacent formations. With the troops in the immediate area retreating, Darius fled the field and was followed by the bulk of his army. Cut off on the Persian left, Bessus began withdrawing with his men. With Darius fleeing before him, Alexander was prevented from pursuing due to desperate messages for aid from Parmenion. Under heavy pressure from Mazaeus, Parmenion's right had become separated from the rest of the Macedonian army. Exploiting this gap, Persian cavalry units passed through the Macedonian line.

Fortunately for Parmenion, these forces elected to continue on to loot the Macedonian camp rather than attack his rear. While Alexander circled back to aid the Macedonian left, Parmenion turned the tide and succeeded in driving back Mazaeus' men who fled the field. He also was able to direct troops to clear the Persian cavalry from the rear.

Aftermath of Gaugamela

As with most battles from this period, casualties for Gaugamela are not known with any certainty though sources indicate that Macedonian losses may have been around 4,000 while Persian losses may have been as high as 47,000. In the wake of the fighting, Alexander pursued Darius while Parmenion rounded up the riches of the Persian baggage train. Darius succeeded in escaping to Ecbatana and Alexander turned south capturing Babylon, Susa, and the Persian capital of Persepolis. Within a year, the Persians turned on Darius and conspirators led by Bessus killed him. With Darius' death, Alexander considered himself the rightful ruler of the Persian Empire and began campaigning to eliminate the threat posed by Bessus.