The debate over the poverty of Christ and his apostles under Pope John XXII (1316-1334) is one of the most famous intellectual controversies of the Middle Ages. The story of the uncompromising pope on collision course with a united Franciscan Order has often been told, most memorably by Umberto Eco in The Name of the Rose. In this book, Patrick Nold sets out to investigate the Franciscan Cardinal Bertrand de la Tour, a man apparently torn between the pope who was his patron and the Order to which he had devoted his life.

The Medieval Church taught that marriage was indissoluble and that consent was the key. Why then could a marriage be dissolved by one spouse joining a religious order after an exchange of consent but before consummation? This question vexed Thirteenth-century academics and, in the fourteenth century, Pope John XXII asked a group of leading theologians and lawyers to study the issue. Position-papers were produced to explain the exception to the rule of indissolubility for chaste monks and nuns, and to explore whether the pope had the power to extend it to celibate priests and deacons. These...