What became of them?
Most popes died while still in office. However, quite a few popes were deposed by one means or another, and at least a handful were assassinated or, in at least one case, lynched by a mob. Only four pontiffs certainly resigned, and one of them, Gregory XII, would have been deposed by the Council of Constance if he had not agreed to its demand for his resignation.
The most recent resignation was by Benedict XVI in 2013. He spent his first few weeks in retirement at the summer residence in Castel Gandolfo. Since then he has only occasionally appeared publicly. I was unable to determine where he is living now, but all of his public appearances have been in Italy. He probably has an apartment in Rome. Hardly anyone seems to care about him, but if you do, you can buy some memorabilia here.
There is no mystery about what happened to Pope Celestine V after he resigned. His successor, Pope Boniface VIII, had him captured and imprisoned. He died shortly thereafter. You can read the fascinating details of his selection and his short pontificate here.
The first pope to resign was Benedict IX, back in 1045. My favorite pope was deposed the previous year, but he gathered his supporters together and regained the Throne of Peter. His second pontificate, however, lasted only a few months. He decided to resign in order to get married. As unlikely as this sounds, I have never read anyone who has posited an alternative explanation. In any case, he evidently negotiated a large sum of cash in exchange for turning the papacy over to his godfather, John Gratian, who became Pope Gregory VI.
At the insistence of the emperor, Gregory was deposed by the Council of Sutri and replaced with the emperor’s choice, who took the name of Clement II. Clement died after only a few months, and Benedict, who apparently never did get married, retook the Throne. Eventually the emperor managed to gather enough force in Italy to force Benedict to flee in July of 1048.
What happened to Benedict after that? It is hard to explain why no one seems to know. Luke, the hegumen (abbot), of the Basilian monastery at Grottaferrata, wrote a biography of one of his predecessors, St. Bartholomew the Younger. In it he asserted that Benedict came to the saint, repented, became a Basilian monk, and died at the monastery. A plaque commemorating these events was reportedly on display at the monastery (which still is in operation 1,000 years later), but the marker was destroyed in the allied bombings of World War II, or so the story goes. The Catholic Encyclopedia endorses this tale.
I have searched diligently for Hegumen Luke’s work, but I have been unable to locate it. It was translated into Italian a few years ago, but my efforts to obtain a copy were unsuccessful. The most complete write-up that I have discovered is in the book Deaths of the Popes by Wendy J. Reardon. Benedict IX’s period as Pope Emeritus is discussed on p. 81.
There were no fact-checkers in the Middle Ages. Is Luke’s story credible? I posed this very question to Santo Lucá, a scholar who has devoted a great deal of study to the documents at Grottaferrata. I discussed his unequivocal negative response in a previous entry.
If Benedict IX did not join the monastery, what happened to him? I wish that I had Mr. Peabody’s Wayback Machine. I would definitely set it to the middle of the eleventh century.