Frederick II clashed with the Pope, but he was no secularist

The Two Powers
By Brett Edward Whalen
University of Pennsylvania Press, 328pp, £70/$80

Pope Gregory IX (1227-1241) may not be among the most forgotten of the vicars of Christ, but neither is he remembered as well as might be expected for a pope who had such a decisive impact on the life of the Church. His patronage, first as Cardinal Hugolino dei Conti and then as occupant of the Chair of St Peter, was a key factor in the Dominicans and Franciscans’ rapid rise to become two of the largest and most influential religious orders, and he was later among the two popes who defended the rights of the Church during one of its most dramatic conflicts with the Holy Roman emperors.