During the Middle Ages, many Europeans imagined that there existed a powerful and marvel-filled Christian realm beyond the lands of Islam ruled by a devout emperor they called "Priest John," or "Prester John." Spurred by a forged letter that mysteriously appeared around 1165 and quickly "went viral" in hundreds of manuscripts across Western Europe, the legend of Prester John and his exotic kingdom was not just a utopian fantasy, but a way to bring contemporary political and theological questions into sharper focus. In this new study, John Eldevik shows how the manuscripts that transmitted the story of Prester John reflect the ways contemporary audiences processed ideas about religious conflict and helped them imagine a new, global dimension of Christianity. It includes an appendix with a new translation of the B recension of The Letter of Prester John.