This is a comprehensive survey of the history of the Church in Western Europe from c. 900 to c. 1125, which is considered both as a set of institutions and as a spiritual body. The first half concentrates on the structures of religious belief and practice in the period 900-1050; the second half concentrates on the revolutionary changes associated with the rise of the papacy to a new level of rulership. It shows how far one can talk of a "reform movement," and how the idea and ideal of papal monarchy became both the prisoner and the leader of those who sought for a renewal of Christian life....