While four popes had resigned, the last was St. Celestine V, who abdicated five months after his election in 1294 at the age of 79.

Pope Boniface confirmed the decree of Pope Celestine V that any pope can freely resign.

Such a year generally occurs when a newly elected pope dies or resigns very early into his papacy.

Before the 21st-century, only five popes unambiguously resigned with historical certainty, all between the 10th and 15th centuries.

Last week, two cardinals said that they believed the pope would resign if his condition got so bad that he felt incapable of carrying on in the job.

In particular, there were doubts whether a pope could resign at all, and who would be authorized to accept such a resignation.

According to canon law, a pope can resign, although the last one who did, Celestine V, did so eight centuries ago.

Although there was much debate, informed opinion generally agreed that a pope could resign.

This becomes necessary when the old pope dies or resigns.

Usually, popes do not resign, though.