How did Philip IV of France challenge the authority of Pope Boniface VIII?

The conflict between King Philip IV of France and Pope Boniface VIII was primarily driven by the king's efforts to tax the clergy to finance military campaigns without papal consent, a practice that violated canon law.12

Philip IV challenged the pope through several escalating actions:

• Defiance of Clericis laicos: In 1296, Boniface issued the papal bull Clericis laicos, which prohibited taxing the clergy under penalty of excommunication. Philip ignored this, as there was no strong opposition in France to his actions.12
• Rejection of Papal Supremacy: The tension intensified in 1302 with the bull Unam sanctam, in which Boniface asserted the absolute primacy of the pope over temporal rulers. Philip responded by challenging this authority.1
• Abduction at Anagni: When Philip’s agents, led by Guillaume de Nogaret and Sciarra Colonna, learned the pope intended to excommunicate the king, they abducted Boniface at his residence in Anagni. Although the pope was rescued after two days, the trauma contributed to his death shortly thereafter.13

This confrontation ultimately weakened the papacy, leading to the Avignon papacy and the subsequent Great Western Schism.1