When Cardinal Peter Rebuli-Juliani, known as the Spaniard (in fact, he was Portuguese; as it later turned out, this was not his last misnomer) was elected pope in 1276, he took the name John XXI. He thought that the previous bishop of Rome named John had already used the number XX. Unfortunately, he made a mistake.
We must admit that the matter was complicated. The reason was the inconsistent numbering of popes in directories, dating back to the end of the 10th century. John Philagathus, using the name John XVI, had illegally claimed to be the bishop of Rome (in Church history, such usurpers are called antipopes). Subsequent John popes were not counted correctly — that is, with the omission of Philagathus. The mistake was finally cleared up some time later, but no one changed the numbering of the long-dead popes in hindsight.
Six centuries without John
The numbering of the popes continued (with no other John XVI than the antipope Philogathus) over more than two centuries. Then came the skip in numbering between Pope John XIX (1024-1032) and Pope John XXI (1276-77), who did not rule for long. A little over a year after his election, John XXI died when a section of the vaulted ceiling of the palace in Viterbo, where he lived, collapsed on top of him. Interestingly, he was probably the only pope to die as a result of an accident — not from old age, illness, or murder. He was also, to date, the only Portuguese on the throne of Peter.
The confusion with John was probably one of the reasons why, after the death of John XXII, who ruled from 1316 to 1334, subsequent bishops of Rome did not pick the name for six centuries. Only in the 20th century did Angelo Roncalli, or John XXIII, dare to do so.
The pope who didn’t exist
Sometimes information turns up claiming a different explanation for the gap in the numbering of the bishops of Rome. The claim is that the missing number is a reminder of the pontificate of Pope Joan (the Latin name Ioanna comes from the name Ioannes), which is said to have been covered up by the Church.
According to one version of the legend, a woman pretending to be a man ruled the Church for two and a half years starting in 855, passing herself off as John VIII. Her ruse supposedly came to light when she became pregnant by her lover and went into labor while mounting a horse during a procession in Rome.
The origin of the story is unknown, but it gained great popularity especially during the Reformation. It was repeated by Protestants as proof of the corruption and stupidity of Catholic clergy, who allowed themselves to be deluded by a woman — in their estimation, an inherently inferior and less intelligent being.
The legend of Pope Joan was so popular that in 1647 the French Protestant David Blondel published a scholarly treatise in Amsterdam, in which he proved that the story was false. Today there is no doubt that there was no such historical figure. Although, of course, several— generally scandalous — novels and films have been made about her.
And today we celebrate...