In this paper we shall focus on the analysis of Innocent III’s power over Philip Augustus and Alfonso IX’s marital issues. Innocent challenged these kings because he could not allow Western monarchs to maintain marital unions which could be censurable in the eyes of his subjects since they were bigamous or had
consanguinity ties below the fourth degree. Innocent was well acquainted with the canonical doctrine and proved himself willing to apply it to kings regardless of the special rights of the sovereigns of France and León over whom the shadow of excommunication and interdict (seven years for the Leonese and two decades for the French king) threateningly loomed; before this unexpected challenge the monarchs dared oppose Rome. This also allows us to compare and contrast the relationship between Innocent and the two monarchs.


Keywords: Innocent III; Philip Augustus; Alphonse IX; Ingeborge of Denmark; Berengaria of Castile; marriage; dissolution; interdict; excommunication.