Innocent III

Innocent III was thirty seven when elected, a trained canon lawyer, and he understood the papal office as a jurisdiction rather than as an honour. His formulation of it was new and was quoted for centuries: the pope is set in the middle between God and man, below God and above man, less than God and more than man. Earlier popes had generally styled themselves vicar of Peter; he preferred vicar of Christ, and the change of title was a change of claim.

He used the instruments a canonist had. He placed France under interdict to force Philip Augustus to take back the wife he had repudiated, and did the same to England over a disputed appointment to Canterbury, holding out until John submitted in 1213 and received his kingdom back as a fief of the papacy. He intervened decisively in the contested imperial election, asserting the right to examine the fitness of a candidate for the empire.

He also had the judgement to recognise what was arriving. When Francis of Assisi came to Rome with a handful of companions and a rule of a few sentences, and when Dominic proposed an order of preachers, Innocent approved both, at a moment when unauthorised popular preaching was exactly what the church was suppressing elsewhere. The mendicant orders became the most effective religious institution of the following century, and the pope who might have crushed them did not.

The council Innocent summoned to the Lateran in November 1215 was attended by some four hundred bishops and eight hundred abbots and priors, with envoys from most of the kingdoms of Europe, and its seventy canons legislated for the whole of western Christendom. It defined the eucharistic change using the word transubstantiated, in what is the term's first conciliar use. It required every Christian who had reached the years of discretion to confess to their own priest at least once a year and to receive communion at Easter, which shaped the religious lives of ordinary people more than any other medieval enactment. It forbade the founding of new religious orders with new rules, and it regulated clerical conduct in detail.

It also imposed on Jews and Muslims in Christian territory a requirement to be distinguishable by their dress, and barred Jews from public office. That legislation is part of the council's record and the atlas states it plainly.

Two crusades belong to the reign and neither went as intended. He called the Fourth Crusade, which was diverted by its Venetian creditors first against a Christian city on the Adriatic and then against Constantinople, sacked in 1204. Innocent had expressly forbidden the attack and denounced it when he learned of it, then accepted the Latin empire that resulted, which is one of the reasons Greek Christians date the real breach with Rome to 1204. He also proclaimed the Albigensian Crusade against the Cathars of southern France in 1208, a campaign of twenty years that destroyed the culture of the region.