Order and ExclusionOrder and Exclusion is a rare and magnificent book of medieval history with clear relevance to today's headlines. Through the lens of the polemics of Peter the Venerable, abbot of Cluny, Dominique Iogna Prat examines the process by which christianity transformed itself into Christendom, a powerful spiritual, social, and political system with pretensions to universality. Iogna Prat's close examination of a set of writings central to the history of