The Wars of Alexander the Great were fought by King Alexander III of Macedon ("The Great"), first against the Achaemenid Persian Empire, under its "King of Kings" Darius III, and then against local chieftains and warlords as far east as Punjab, India. Alexander the Great was one of the most successful military commanders of all time. He was undefeated in battle. By the time of his death, he had conquered most of the world known to the ancient Greeks.