THE LEGEND OF Prester John is not merely a curious footnote in the history of medieval folklore or popular literature, but an important story about one culture's desire to imagine itself in a broader, global political and religious context, and the way those desires were instantiated within its books and manuscripts. Europe during the medieval period was economically and politically underdeveloped compared to Byzantium, the Muslim Middle East, and the great empires of Central and East Asia, yet harboured grand visions of somehow also being part of, and dominating, that wealthier and more sophisticated world. The world historical consequences of such thinking cannot be understated. As scholars like Geraldine Heng, Michael Brooks, and Adam Knobler have shown, this desire, with its supercessionist underpinnings, remained a significant driving force behind European exploration and colonization well into the early modern period.

Even as European knowledge of Africa and Asia accumulated and evolved during the Age of Exploration, the matter of Prester John never entirely disappeared from the conversation about the world and Europe's place within it. As Europeans gained more empirical knowledge of the wider world, it forced an ongoing reconciliation, and sometimes confrontation, with received wisdom and authority. One can trace an evolution of historical thinking and methodology in the early modern discussions of Prester John. Instead of "finding" Prester John, questions turned to whether he had ever been a historical figure, or explaining how he shifted from being an Asian to being an African, namely Ethiopian, ruler, particularly in the light of new geographical, linguistic, and historical information. The French polymath Joseph Scaliger, for example, seeking to reconcile various medieval accounts of Prester John's location, proposed, via a series of rather strained etymologies of the name, that he had been an Asian ruler who had fled to Africa to escape the Mongol conquests, giving his name to the dynasty of Ethiopian rulers, as the Portuguese claimed.