<P> No more of the tale is recorded until about 1165 when copies of what was certainly a forged Letter of Prester John started spreading throughout Europe . An epistolary wonder tale with parallels suggesting its author knew the Romance of Alexander and the above - mentioned Acts of Thomas, the Letter was supposedly written to the Byzantine Emperor Manuel I Comnenus (1143--1180) by Prester John, descendant of one of the Three Magi and King of India . The many marvels of richness and magic it contained captured the imagination of Europeans, and it was translated into numerous languages, including Hebrew . It circulated in ever more embellished form for centuries in manuscripts, a hundred examples of which still exist . The invention of printing perpetuated the letter's popularity in printed form; it was still current in popular culture during the period of European exploration . Part of the letter's essence was that a lost kingdom of Nestorian Christians still existed in the vastnesses of Central Asia . </P> <P> The credence given to the reports was such that Pope Alexander III sent a letter to Prester John via his physician Philip on September 27, 1177 . Nothing more is recorded of Philip, but it is most probable that he did not return with word from Prester John . The Letter continued to circulate, accruing more embellishments with each copy . In modern times, textual analysis of the letter's variant Hebrew versions has suggested an origin among the Jews of northern Italy or Languedoc: several Italian words remained in the Hebrew texts . At any rate, the Letter's author was most likely a Westerner, though his or her purpose remains unclear . </P> <P> In 1221, Jacques de Vitry, Bishop of Acre, returned from the disastrous Fifth Crusade with good news: King David of India, the son or grandson of Prester John, had mobilized his armies against the Saracens . He had already conquered Persia, then under the Khwarezmian Empire's control, and was moving on towards Baghdad as well . This descendant of the great king who had defeated the Seljuks in 1141 planned to reconquer and rebuild Jerusalem . Controversial Soviet historian and ethnologist Lev Gumilev speculated that the much reduced crusader Kingdom of Jerusalem in the Levant resuscitated this legend in order to raise Christian hopes and to persuade European monarchs who had lost interest by that time in getting involved in costly crusades in a distant region that was far removed from their own states and affairs . </P> <P> The bishop of Acre was correct in thinking that a great King had conquered Persia; however "King David", as it turned out, was the Tengrist Mongol ruler, Genghis Khan . His reign took the story of Prester John in a new direction . Though Genghis was at first seen as a scourge of Christianity's enemies, he proved to be tolerant of religious faiths among those subjects that did not resist the empire, and was the first East Asian ruler to invite clerics from three major religions (Christianity, Islam, and Buddhism) to a symposium so that he might learn more about their beliefs . The Mongol ruler was also reputed to have a Nestorian Christian favorite among his many wives, whom the Europeans imagined as influential in the disastrous Mongol sack of Baghdad . </P>

In medieval european society was the king of the pope the most powerful figure