The course deals with the origins of Christianity and the first eleven centuries of its expansion into a major institutional, social, and intellectual force shaping Western Europe. The central themes are the mechanisms and conditions shaping this expansion, rather than a chronological account, to present this process as a model of institutionalization of religious movements. The emphasis will be on patterns of crisis and reform; that is, on conflicts arising within the church itself; as results of its dealings with the "outside" world; and how these crises were resolved. The course is based on the study of primary sources and will include problems of historical method. Requirements, beyond a basic familiarity with Roman and Medieval history, are one midterm, one final, and a book review.