Alexander, son of Philip II of Macedon, was a king and general since he was a teenager. What justifies his title ‘The Great’?
Greatness can be based on achievement. Alexander conquered vast tracts of territory in his short life; but also destroyed much, notably in Persia. After his death his empire fragmented and was marked by conflict.
Or perhaps his posthumous impact on the world makes him great. He did introduce the idea of absolute monarchy, built many cities named Alexandria, and gave the known world Greek as a common language. This facilitated trade and communications.
Finally, Alexander’s legend has been embellished to make him an almost magical person. Does this make him ‘great’?
History is what we make it, as much as what happened.