Pope Innocent III In the Middle Ages, the pope was the supreme
head of the church in England: not until the Reformation, over
300 after Magna Carta, did Henry VIII reject papal supremacy.
Innocent III was elected pope in 1198 and reigned until his
death in 1216. His papacy, which coincided almost exactly with
King John's reign of 1199-1216, saw repeated attempts to enforce
papal authority over secular rulers, campaigns to rid the church
of heretics and the Fourth Crusade. In ecclesiastical
government, Innocent III's determination to impose his judicial
authority over the whole Latin church culminated in the major
reforms of the Fourth Lateran Council of 1215. By the time of
his death in 1216, Innocent had set in place the framework for
the power of the 13th-century papacy.