The eleventh-century papal reform transformed western European Church and society and permanently altered the relations of Church and State in the west. The reform was inaugurated by Pope Leo IX (1048-54) and given a controversial change of direction by Pope Gregory VII (1073-85). This book contains the earliest biographies of both popes, presented here for the first time in English translation with detailed commentaries. The biographers of Leo IX were inspired by his universally acknowledged sanctity, whereas the biographers of Gregory VII wrote to defend his reputation against the hostility generated by his reforming methods and his conflict with King Henry IV. Also included is a translation of Book to a Friend, written by Bishop Bonizo of Sutri soon after the death of Gregory VII, as well as an extract from the violently anti-Gregorian polemic of Bishop Benzo of Alba (1085) and the short biography of Leo IX composed in the papal curia in the 1090s by Bishop Bruno of Segni. These fascinating narrative sources bear witness to the startling impact of the papal reform and of the 'Investiture Contest', the conflict of empire and papacy that was one of its consequences. An essential collection of translated texts for students of medieval history.