In that age the papacy was sometimes long vacant, because the cardinals, who were the highest in rank of the Roman clergy, and to whom the choice of a pope belonged, could not agree. In order to get over this difficulty, rules were made for the purpose of forcing the cardinals to make a speedy choice. Thus, at a council which was held by Pope Gregory X at Lyons, in 1274 (chiefly for the sake of restoring peace and fellowship between the Greek and Latin Churches), a canon was made for the election of popes. This canon directed that the cardinals should meet for the choice of a new pope within ten days after the last pope's death; that they should all be shut up in a large room, which, from their being locked in together, was called the "conclave" ("Con" meaning "together" and "clave" meaning "a key"); that they should have no means of speaking or writing to any person outside, or of receiving any letters; that their food should be supplied through a window; that, if they did not make their choice within three days, their provisions should be stinted, and if they delayed five days more, nothing should be given them but bread and water. By such means it was thought that the cardinals might be brought to settle the election of a pope as quickly as possible.
We can well believe that the cardinals did not like to be put under such rules. They contrived that later popes should make some changes in them, and tried to go on as before, putting off the election so long as seemed desirable for the sake of their own selfish objects. At one time, when there had been no pope for six months, the people of Viterbo confined the cardinals in the public hall of their city until an election should be made. At another time, the cardinals were shut up in a Roman monastery, where six of them died of the bad air. But one cardinal, who was more knowing than the rest, drove off the effect of the air by keeping up fires in all his rooms, even through the hottest weather; and at length he was chosen pope.
On the death of this pope, Nicolas IV (AD 1292), his office was vacant for two years and a quarter; and when the cardinals then met, it seemed as if they could not fix on any successor. But one day one of them told the rest that a holy man had had a vision, threatening heavy judgments unless a pope were chosen within a certain time; and he gave such an account of this holy man that all the cardinals were struck at once with the idea of choosing him for pope. His name was Peter of Murrone. He lived as a hermit in a narrow cell on a mountain; and there he was found by certain bishops who were sent by the cardinals to tell of his election. He was seventy-two years of age; roughly dressed, with a long white beard, and thin from fasting and hard living. He could speak no other tongue than the common language of the country-folks around, and he was quite unused to business of any kind, so that he allowed himself to be led by any one who would take the trouble. The fame of Peter's holiness had been widely spread, and he was even supposed to do miracles; so that his election was welcomed by multitudes. Two hundred thousand persons flocked to see his coronation, where the old man appeared in the procession riding on an ass, with his reins held by the king of Naples on one side and by the king's son on the other (AD 1294).
This king of Naples, Charles II, got the poor old pope completely into his power. He made him take up his abode at Naples, where Celestine V (as he was now called) tried to carry on his old way of life by getting a cell built n his palace, just like his old dwelling on the rock of Fumone; and into this little place he would withdraw for days, leaving all the work of his office to be done by some cardinals whom he trusted.
Other stories are told which show that Celestine was quite unfit for his office. The cardinals soon came to think that they had made a great mistake in choosing him; and at length the poor old man came to think so too. One of the cardinals, Benedict Gaetani, who had gained a great influence over his mind, persuaded him that the best thing he could do was to resign; and, after having been pope about five months, Celestine called the cardinals together and read to them a paper, in which he said that he was too old and too weak to bear the burden of his office; that he wished to return to his former life of quiet and contemplation. He then put off his robes, took once more the rough dress which he had worn as a hermit, and withdrew to his old abode. But the jealousy of his successor did not allow him to remain there in peace. It was feared that the reverence in which the old hermit was held by the common people might lead to some disturbance; and to prevent this he was shut up in close confinement, where he lived only about ten months. The poorer people had all manner of strange notions about his holiness and his supposed miracles; and about twenty years after his death he was admitted into the Roman list of saints.