Diarmaid MacCulloch starts his study of the Reformation, All Things Made New, with a sketch of the medieval world. It's a bit rosy, emphasizing the unity of medieval Europe: “The most noticeable characteristic of Western Europe in what we call the Middle Ages was its cultural and religious unity – unity through a common alignment with the Pope in Rome, and a common language for worship and scholarship, Latin. Western Europeans who know anything about their history tend to take this united medieval phase of it for granted, in the way that when we are growing up, we take for granted the environment around us as the norm by which everything else is judged.”

Even if we darken the hues, MacCulloch's claim about the uniqueness of medieval world is arresting: “it is unique in human history for a region to be so dominated by a single form of monotheistic religion and its accompanying culture for so long. Only the Wahhabi variety of Islam in what is now Saudi Arabia comes close to such a claim to exclusive dominance, and for a far shorter period; I would challenge you to name another example of similar intensity. Islam has the concept of the umma, the shared community of Muslims, but this has not resulted in the sort of unity possessed by 1 medieval Western Christendom. The dominance of the Church which looked to the Bishop of Rome was a freak in human experience, albeit a freak with profound consequences for the present day. Its break-up in the sixteenth century was a return to the normality of human history.”