Alexander the Great defeats Persian King Darius III at Gaugamela

Historical records mark October 1 as the anniversary of the Battle of Gaugamela in 331 BC, where Alexander the Great defeated the Persian King Darius III. This decisive victory allowed Alexander to complete his conquest of the Persian Empire. During this battle, Alexander’s beloved horse, Bucephalus, was killed.

The conflict occurred on an open plain located between modern-day Mosul and Erbil in Iraq. Following his previous victory at the Battle of Issus, Alexander moved south through the Mediterranean coast and Syria to secure imperial treasures. Despite attempts by Darius III to negotiate the release of the royal family, Alexander sought retribution for previous grievances against the Greeks. While historical accounts vary on exact troop numbers, the Persian forces significantly outnumbered the Macedonian and allied troops, which included approximately 40,000 hoplites and 7,000 cavalry.