As Cardinal Hugo and as pope, Gregory was one of the dominant figures in the history of the papacy of the High Middle Ages. Coming to prominence under Pope Innocent III, Hugo played an important political role, particularly as legate on various occasions, as well as being a major promoter of the new religious orders. As pope, his battle with Emperor Frederick II is one of medieval history’s most absorbing conflicts. But he also acted as peacemaker, promoter of the Crusades, instigator of mission for the sake of conversion, refomer of the Curia, patron of arts and liturgy, and as a...