By Lindsey Rosso
Honors Thesis, Vanderbilt University, 2003
Introduction: The sky hung low in the Middle Ages; God and the eternal were ever-present. For medieval Christians whose lives revolved around religion, the sacraments and offices of the Church were staples of life, and the deprivation of those necessities was a calamity. During the High Middle Ages, popes Gregory VII (1073-1085) and Innocent III (1198-1216) both sought to increase their spiritual and political authority over rival kings Henry IV and John I of England through excommunication, a weapon that excluded the monarchs from Christian society.
Innocent also exercised his authority of laying England under interdict, which extended the sentence of excommunication to all of John’s subjects. Spurred by conflicts over the issue of lay investiture, Gregory and Innocent exerted and legitimized their power with these sentences, which both had the effect of stripping the sovereign of his authority and turning his subjects against him. The justification for these tactics developed and strengthened the institution of ‘papal monarchy,’ which established the pope as the supreme secular and religious leader, at a time when the Church’s authority and laws were still developing.
This thesis will examine and compare how excommunication and interdict augmented papal power during the reigns of Gregory VII and Innocent III. Because they used the sentences against strong kings, Gregory and Innocent represented milestones in the evolution of the ideal of papal monarchy. This thesis seeks to understand how the popes threatened and intimidated Henry and John with excommunication and interdict. In what ways did the arguments for these tactics represent new exertions of papal power and steps toward the ideal of papal monarchy? To what extent did Gregory and Innocent rely on Church canon law, and the Bible in defending their claims for power? Finally, how did each legitimize his excommunication of the monarch who opposed him and assert the papacy as the supreme institution of medieval Europe?