The Crusades: The Authoritative History of the War for the Holy Land

by Thomas Asbridge

the barely contained animosity between Frederick II and Gregory IX resurfaced once more in 1239. The emperor was again excommunicated and, this time, the pope called for a fully fledged crusade against his Hohenstaufen opponent–now defamed as an enemy of Christendom and ally of Islam. Another crusade against the emperor was announced in 1244 and this led to open warfare that rumbled on until Frederick II’s death in December 1250. Resolute in its desire to uphold and advance the strength of the Church, the papacy had finally embraced the idea of wielding the weapon of holy war against its political enemies. Similar calls to arms would follow for decades, even centuries, to come. These prompted some outcry, occasionally even vociferous condemnation, but nonetheless many willing recruits took the cross–content to fight on Latin soil against fellow Christians in return for an indulgence. Of all the criticisms levelled at the papacy by contemporaries for this dilution of the ‘crusading ideal’, the most telling was the frequent complaint that the true battlefield in the holy war lay in the East. It is certainly true that, over time, Rome’s redirection of crusade armies–both within western Europe and to other theatres of conflict in Iberia, the Baltic and the faltering state of Latin Romania–served further to isolate and enfeeble Frankish Outremer.