Before the mid-eleventh century the pope was far from being the active leader of the Church that he is today: he restricted himself to the local concerns of the diocese of Rome and was virtually ignored by the outside world. This book is a study of the transformation of the role of the pope in the late eleventh and twelfth centuries, from which he emerged as monarch of the universal Church, dedicated to reform and to making the Church independent of secular control. The most important role in the new model government was given to the cardinals, who henceforward were the principal advisers, agents, and electors of the popes. These developments were accelerated by schism and political conflict: on three occasions the lawful pope was driven into exile by an antipope supported by a powerful secular ruler. Professor Robinson's text emphasises the growing importance of the college of cardinals and the practical aspects of papal government. It offers the most detailed analytical study yet available of this key period in the history of the papacy.