Boniface VIII
Benedetto Caetani · 1294 – 1303
Issued the most extreme claim of papal authority ever written, then was humiliated by the French king who nearly destroyed him.
Boniface VIII made enormous claims and couldn't back them up. His bull Unam Sanctam declared that submission to the pope was necessary for salvation, the strongest assertion of papal supremacy in history. He clashed with King Philip IV of France over the right to tax clergy, and Philip fought back viciously. In 1303, French agents and Italian enemies stormed Boniface's palace at Anagni and reportedly roughed up the elderly pope. He was rescued but died weeks later, broken and humiliated. Dante put him in hell in the Divine Comedy, which gives you a sense of his reputation even among contemporaries. Boniface's pontificate marked the beginning of the end for medieval papal political power. Within two years, the papacy would relocate to Avignon under French control.
Overreach and Collapse
Boniface's story is a cautionary tale about confusing spiritual authority with political power. He claimed more than any pope before him and lost more than most. The gap between his words and his actual power was enormous, and his enemies exploited it ruthlessly.