Gregory VII resolutely confronted the challenge posed by secular power during the Investiture Controversy and set standards for the freedom of the Church. However, despite the hour of his greatest triumph in 1077 at Canossa, he ultimately had to concede defeat in the struggle for papal supremacy against his opponent Henry IV. Rudolf Schieffer describes the development of Hildebrand-Gregory, the influences on his reform ideas, and his actions as pope. His portrayal, which is both closely tied to the sources and thoughtfully balanced, paints a vivid picture of the pope who, like few others, shaped the self-understanding of the medieval Church.