The story of Pope Joan is an interesting one.

[A] learned woman in male disguise managed to get herself elected pope. She reigned for two years. During a procession on its way to the Lateran Joan gave birth to a child, which in the most dramatic fashion imaginable unmasked the deception. She died immediately afterward. (A History of the Popes, John W. O’Malley, S.J., pg 131-2)

The event was immortalized in several paintings.

But it never happened.

Basically, the stories were believed—even in Catholic circles—for years.

Versions differed of course in detail, including the years when Joan reigned, though it was never set in the present or near-present. What the legend indicated was how ready the faithful were to believe the worst. (O’Malley, 132)

There were a number of versions of the story, which originated in the 11th century and continued through the 17th. Some claim she died of natural causes. Other versions depict an angry mob that killed her after her deception was revealed. Few are specific with dates or years—her reign is usually described as just long ago to not be common knowledge. The biggest evidence against her existence is that there are no substantial gaps in the succession of popes to match the stories.

As to why the story persists, there are a number of reasons. The first is that the papacy has a less than unblemished history. Corruption and even depravity were all too common. Dissatisfaction with the popes’ rule over the Papal States was commonplace. Calls for reform were just as common, which obviously included the Reformation at later points in the story.

By the end of the [13th] century [which marks the high point of the legend] the prestige of the papacy had declined from the high level achieved by Innocent III. The popes’ constant involvement in political and military conflicts took its toll on their reputations, even though they often, given the assumptions of the age, could hardly have stayed aloof from them. They faced growing criticism because of levies they imposed for financing crusades and for other causes and faced it as well for what sometimes seemed the ostentatious wealth of churchmen, especially the cardinals and the pope himself. A radical branch of the Franciscan order, the “Spirituals,” preached a poverty for the church and the papacy that sounded suspiciously like destitution and especially on this issue they became dangerous antipapal propagandists. Even outside Franciscan circles expectations that God was about to send an “angel pope” to rescue the church from worldliness circulated fairly widely.

This was the sour context in which the legend of Pope Joan emerged. (Again, O’Malley)

The story of Pope Joan serves all of these ideas. It is excellent anti-papal satire. It can be used to point out the flaws in the papacy or Catholicism. It is a fantastic account of just how hypocritical the papacy has been at points in its history. It can be used as an example as to why we should destroy the Catholic Church, or why it needs to be reformed. So, while Pope Joan never existed, the legend of her existence points to real problems that faced the papacy and real efforts to reform the Church.