The Vatican’s official records state that all of the more than 260 Catholic popes have been men, but according to a medieval legend, a lady pontiff may have reigned for a brief period in the ninth century. As the story goes, this “Pope Joan” was a young woman who disguised herself as a man and entered into religious training. After distinguishing herself as a scholar, she rose through the church ranks and was elected Pope John VIII in the year 855. She went on to rule for more than two years, her gender always carefully concealed beneath her flowing holy robes. Her secret was only revealed in 858, when she unexpectedly went into labor during a papal procession. Some accounts allege that she died in childbirth, while others claim her enraged followers dragged her behind a horse and stoned her to death.

The forgotten “popess” first planted herself in the medieval imagination in the 13th century, when her story appeared in chronicles by the Dominican friars Jean de Mailly and Stephen of Bourbon. She was later christened “Joan,” and went on to become a widely accepted part of Catholic history. The 14th century writer Giovanni Boccaccio mentioned her in a book about famous women, and her image graced paintings, sculptures and tarot cards. She was even briefly included in a collection of papal busts in Italy’s Siena Cathedral.

Despite her medieval celebrity, most historians now dismiss Pope Joan as a myth. There are no reliable references to her during her lifetime, and her supposed reign overlaps with those of two well-documented pontiffs, Leo IV and Benedict III. While a few scholars contend that she may have existed later or been expunged from church histories, the more likely explanation is that her story was anti-papal satire popularized by disgruntled monks, early Protestants and other critics of the Catholic Church.