October 1

Battle of Gaugamela — Alexander Defeats Persia

Alexander the Great defeated Darius III of Persia at Gaugamela despite being outnumbered 3-to-1, using a brilliant oblique attack that created a gap in the Persian line. Darius fled the battlefield; the Persian Empire collapsed within months.

Gaugamela was the decisive battle that destroyed the Persian Empire and made Alexander master of the known world, spreading Greek culture from Egypt to India.