IN 212 CE the emperor Caracalla decreed that all the free inhabitants of the Roman Empire, wherever they lived, from Scotland to Syria, were Roman citizens. It was a revolutionary decision, which removed at a stroke the legal difference between the rulers and the ruled, and the culmination of a process that had been going on for almost a millennium. More than 30 million provincials became legally Roman overnight. This was one of the biggest single grants of citizenship – if not the biggest – in the history of the world.
