The essays in this volume centre upon the epoch-making papacy of Gregory VII (1073-85), and complement the author's major study of the pope. They look at the formation and expression of Gregory's ideas, notably in relation to simony and clerical chastity, and emphasise his religious motivation; attention is also given to the impact of his pontificate on the Anglo-Norman lands and Scandinavia. The book further includes extended discussion of the contrasting figure of Lanfranc, Archbishop of Canterbury (1070-89), and of the complex question of the interaction between him and Pope Gregory.