While living like this, in 1244, he founded the order subsequently named after him, the Celestines. A new religious community was formed, and Pietro gave them a rule formulated in accordance with his own practices. In 1264 the new institution was approved by Urban IV. Having heard that it was probable that Pope Gregory X, then holding a council at Lyon, would suppress all such new orders as had been founded since the Lateran Council had commanded that such institutions should not be further multiplied, Pietro went to Lyon. There he succeeded in persuading Gregory to approve his new order, making it a branch of the Benedictines and following the rule of Saint Benedict, but adding to it additional severities and privations. Gregory took it under papal protection, assured to it the possession of all property it might acquire, and endowed it with exemption from the authority of the ordinary. Nothing more was needed to ensure the rapid spread of the new association and Pietro lived to see himself as "superior-general" to thirty-six monasteries and more than six hundred monks. Pietro, however, cannot be accused of ambition or the lust of power when a monastic superior, any more than when he insisted on divesting himself of the papacy, to which he was subsequently raised. As soon as he had seen his new order thus consolidated he gave up the government of it to a certain Robert, and retired once again to a still more remote solitude to give himself up more entirely to solitary penance and prayer. Shortly afterwards, in a chapter of the order held in 1293, the original monastery of Majella being judged to be too desolate and exposed to too rigorous a climate, it was decided that Abbazia Morronese in the plains of Sulmona should be the headquarters of the order and the residence of the general-superior, as it continued to be until the order was extinguished in the 19th century. Election as pope The cardinals assembled at Perugia after the death of Pope Nicholas IV in April 1292. After more than two years, a consensus had still not been reached. Pietro, well known to the cardinals as a Benedictine hermit, sent the cardinals a letter warning them that divine vengeance would fall upon them if they did not quickly elect a pope. Latino Malabranca, the aged and ill Dean of the College of Cardinals cried out,