At the age of 30, Alexander the Great created one of the largest empires in history, stretching from Greece to northwest India. During that time, he was undefeated in battle. Alexander the Great is known today as one of the greatest military minds ever and is considered one of the greatest rulers in ancient history. He used a combination of pragmatic tactics and careful planning to take control of vast territories and defeat enemies in Egypt, India, and the Achaemenid Empire, among others.