"Historians of the medieval church have long recognized the crucial character of the late eleventh and twelfth centuries for the history of the papacy. In this volume we have a superb treatment of the development and transformation of this institution. It effectively summarizes the state of current scholarship and, at the same time, provides independent interpretations which are cogent and reliable." Paul W. Knoll, Church History "The work is unquestionably immensely valuable to students, and particularly teachers, of the mid-Middles Ages. Robinson's exhaustive treatment of all the matters he includes and his careful and complete notes to the original sources and to an immense body of secondary writing over the past century make it an unparalleled resource tool." Anne Gilmour-Bryson, Speculum