The story centres on the widely made claim that, when numerised (i.e., when those letters in the 'title' that have Roman numeral value are added together as in a chronogram) they produce the number 666, described in the Book of Revelation as the Number of the Beast (the Antichrist), who wears multiple crowns (identified by some as the triple tiara).
VICARIVS·FILII·DEI with the non-numeric letters removed gives: VICIVILIIDI = 5 + 1 + 100 + 1 + 5 + 1 + 50 + 1 + 1 + 500 + 1 = 666 This claim has been made by some Protestant sects who believe that the Pope, as head of the Roman Catholic Church, is the Beast or the False Prophet mentioned in the Book of Revelation.
Jean de Mailly, a French Dominican at Metz, places the story in the year 1099, in his Chronica Universalis Mettensis, which dates from approximately 1250 and gives what is almost certainly the earliest account of the woman who became known as Pope Joan.
The First Complete Documentation of the Facts behind the Legend, is assuming that a more plausible time-frame would be 1086–1108, when there were a lot of antipopes, and the reign of the legitimate popes Victor III, Urban II, and Paschal II was not always established in Rome, since this city was occupied by Henry IV, Holy Roman Emperor, and later sacked by the Normans.
After two or five years of reign, "Pope Joan" became pregnant and, during an Easter procession, she gave birth to the child on the streets when she fell off a horse.
As a consequence, certain traditions stated that popes throughout the medieval period were required to undergo a procedure wherein they sat on a special chair with a hole in the seat.
A cardinal would have the task of putting his hand up the hole to check whether the pope had testicles, or doing a visual examination.
However, there is no solid evidence for any of these claims; in history, only one document has ever been attributed to Jesus himself, the Letter of Christ and Abgarus.