In 336 B.C., Alexander III of Macedon succeeded his father, Philip II, in becoming king of Greece at the age of twenty. Alexander was not content to rule Greece. By age thirty, he had conquered so many nations that his rule extended from Greece to northwestern India. Alexander was undefeated in battle and is considered one of the greatest military commanders in history. No wonder he was called Alexander the Great. But did you know that Alexander was tutored until the age of 16 by the Greek philosopher Aristotle?