At the Battle of Gaugamela in 331 BCE, Alexander the Great’s cavalry made a decisive charge against the Persian forces led by King Darius III. As Alexander’s troops broke through the Persian lines, Darius, realizing the battle was lost, fled the battlefield in fear for his life. His retreat marked the collapse of the Persian army, signaling the end of the Achaemenid Empire’s resistance against Alexander and solidifying his conquest of Persia | Kings & Generals