The author of The Travels of Sir John Mandeville remains unknown but many scholars believe it was written by an exiled Irish physician living in France. It circulated around Europe in the late fourteenth century and includes several adventurous and oudandish stories. The stories are now known to be hoaxes, but they nonetheless serve as a mirror to the medieval mind. The legendary story of Prester John, about an all-powerful ruler who receives the rite of baptism and ordination, appears first in the chronicle of Otto of Freising in 1145, but probably originated during the expansion of Christianity many years earlier. The validity of the story was still being seriously debated as late as 1646 and the Nuremberg globe of Renaissance geographer Martin Behaim includes Mandeville's magnetic rocks between Java Major and the mainland of India.

This emperor, Prester John, holds full great land, and hath many...