Edward Gibbon spent six volumes and most of his adult life explaining why Rome fell, and he was not the first. The question has generated more scholarly production than almost any other in historical study, a volume that says less about Roman history than about the intellectual needs of subsequent civilizations that measured themselves against Rome’s shadow. Every generation finds its own answer, and every answer reveals as much about the present as about the fifth century.

The Battle of Zama in 202 BC ended the Second Punic War and established Roman dominance over the western Mediterranean for the next three centuries. It was the only battle Hannibal ever lost in a pitched field engagement, and it was lost to the one Roman general who had studied his methods carefully enough to use them against him. Scipio Africanus was thirty-four years old when he defeated Hannibal at Zama. He had spent his career learning from Carthage’s mistakes and Rome’s. The education was complete.