Pope Leo IV died in 855. Pope Benedict III succeeded him in 858. The three years between saw one of the most controversial characters ever to appear in the Vatican, Pope John VIII, who was secretly a woman, often referred to as Pope Joan I.
Born in the darkest of the dark ages, when women were declared to be the property of men by the church, Pope Joan (her real name remains unknown) impersonated a man in order to gain access to education, became a monk, and by virtue of a superior command of religious knowledge and political skill was eventually elected Pope.
Pope Joan's masquerade was undone by her own sexual appetites, which matched those of the other Popes (See Pope Alexander VI). She became pregnant and had the misfortune to go into labor during a Papal procession from the Patriarchum, the official Pope's Residence (now St. Lateran's) along the "Via Sacra" (The Sacred Road, now Via S. Giovanni) to St. Peter's Basilica at the Vatican, suffering a miscarriage in full public view. The crowd, not quite willing to accept this particular "miracle", promptly stoned Pope Joan to death and she was buried in an unmarked grave with her baby.
Up until the 16th century, the Catholic church acknowledged Pope John VIII's (Pope Joan's) existence.
In 1276, Pope John XX changed his name to Pope John XXI after discovering the existence of John VIII (Pope Joan) in the Vatican archives. Even though the Via Sacra was the shortest and most direct route between the Patriarchum and the Vatican, all later Papal Processions went by another path.
Following the stoning of Pope Joan and up until the 16th century, the Papal Consecration ceremony included a process politely called the "chair exam". Papal candidates were required to sit in the "Sella Stercoraria", an ornate version of an outhouse seat with a hole in the bottom through which their male genitals could be observed by an official examiner who would then proclaim, "Mas nobis nominus est" -- "Our nominee is a man." Only then was the newly crowned Pope handed the keys to St. Peter's.
The official position of the Catholic Church today is that Pope John VIII (Pope Joan) was an invention of Protestants intent on embarrassing the Catholics.
However, despite efforts by the holy inquisition to erase any and all records of Pope John VIII (Pope Joan), more than 500 ancient manuscripts by acknowledged period authors (Petrarch and Boccaccio) and high ranking clergy have been uncovered describing the reign of Pope John VIII (Pope Joan).
Pope Joan's statue can be seen at the Cathedral of Sienna, labeled as being Pope Zacharias by order of Pope Clement VIII in 1601.
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