Popes, Overlords and Frontiers: A Comparative Case Study of Papal Communication with the Iberian Peninsula and British Isles

This study compares two papal letters very distant in time and addressed to different geographical contexts: the letter of Gregory the Great to Æthelbert of Kent (601) and that of Gregory VII to Alfonso VI of Castile and León (1081). The two cases present interesting similarities that allow comparative study. In both contexts, in fact, we have sovereigns extending their hegemony above other territorial lords on both sides of the Christian frontier (Christianity/Paganism and Christianity/Islam). The papacy seems to be aware of this position of political superiority of the two kings-overlords and takes advantage of it to expand frontier of the Ecclesia and, at the same time, ensure its own ecclesiastical hierarchical superiority. This comparison makes it possible to investigate the theme of the papacy's communication and the relationship between the Apostolic See and the frontiers of Christendom, much in vogue in contemporary historiography.