Gaugamela

Alexander's march through Mesopotamia

After the Macedonian army had crossed the Tigris, a near-total lunar eclipse occurred on 20–21 September 331 BC. Four days later, Alexander's army spotted members of Mazaeus' cavalry and captured one or two, who gave information about the location of Darius' army at Gaugamela, some eight miles away. In light of the ground-flattening efforts taking place at Gaugamela, Alexander determined that Darius did not intend to change locations, and allowed his troops four days to rest before engaging Darius' army in battle. Following the calculations, the date of the Battle of Gaugamela must have been 1 October in 331 BC.