Letters 113.29

Alexander, to be sure, harried and put to flight the Persians, the Hyrcanians, the Indians, and all the other races that the Orient spreads even to the Ocean; but he himself, as he slew one friend or lost another, would lie in the darkness lamenting sometimes his crime, and sometimes his loss; he, the conqueror of so many kings and nations, was laid low by anger and grief! For he had made it his aim to win control over everything except his emotions.

Seneca, Letters to Lucilius 113.29, translated by Richard Mott Gummere