"In the twelfth and thirteenth centuries the Western Christian Church, through its Popes, was also aware of the existence of a Mysterious Spiritual Abode and Brotherhood in the heart of Asia, headed by the then famous Prester John, as this Great Spirit called himself. This Prester John, from time to time, sent admonishing and warning notes to the Popes and other heads of the Church. According to historical records, one of the Popes sent an embassy to Prester John in Central Asia. One can well imagine the purpose of such an embassy, and, of course, after diverse misfortunes and vicissitudes, this embassy returned, unable to find the Spiritual Citadel. Yet Prester John continued to send his admonishing notes."
January 1, 1970
https://en.wikiquote.org/wiki/Prester_John