A popular collection of essays entitled “The Templar Papers: Ancient Mysteries, Secret Societies, and the Holy Grail” contains an article by Sandy Hamblett in which she attempts to answer some questions regarding the Knights Templar origins. In order to prove the possibility of hermetic inclinations on the part of some Crusaders, she alludes to a letter written Gerbert of Aurillac (who later became Pope Sylvester II). Hamblett quotes Jean Markale’s book The Templar Treasure at Gisor.
This Pope had (some 100 years before the first crusade) suggested in a letter that he “hopes France would recover the holy places so that a search could be made for the keys to the Universal Understanding hidden there.” This of course suggests that knowledge of some sort was known, and that it would necessitate a search of the Holy Places. (p. 34)
This sounds like very unusual words for the future pope to utter, and with good reason: Hamblett is not quoting the letter (as it might appear), but instead its paraphrase or summary, given by Markale. However, Jean Markale adds that the letter’s authenticity has never been proved! Thus far, I was unable to find any source that actually contains this letter. It does indeed seem that it would be interesting and possibly even relevant to the history of the Knights Templar. But at the moment I am not even sure that this letter even exists.