Bruno was the obvious candidate as his successor – nearly 50, known and trusted, and experienced in administration. But in 1077 he and two of his fellow-canons at Reims had made a vow to abandon the world and enter the religious life. It had not been possible to act on that vow at the time. Now it was. Bruno fled.

  He went first to join St Robert, who had settled at Molesme and gathered followers round him, who were later to become the Cistercian Order. But this was not his vocation. In 1084, with six of his companions, he presented himself to St Hugh of Châteauneuf, Bishop of Grenoble, who installed them in a wild spot called Chartreuse, not far from Grenoble, among steep rocks and snow-covered mountains. They built a small monastery where they lived in deep retreat and poverty, entirely occupied in prayer and study.

  In 1088 one of Bruno’s pupils from Reims became Pope Urban II and resolved to continue the work of reform begun by Gregory VII. In 1090 Urban summoned Bruno to Rome to help. Narrowly avoiding being elected bishop again – of Reggio in Calabria, this time, which he escaped by getting one of his former pupils to be elected instead – Bruno managed to persuade the Pope to let him resume the solitary life. He founded a new monastery in the diocese of Squillace in Calabria, and for the rest of his life led an amphibian existence, being called away from time to time to help the Pope in his project of reform, but always returning.

  Bruno pioneered the “mixed” form of religious life, of hermits who live together in a community. He did not plan to found an Order, but the seed he had planted at Chartreuse grew into the Carthusian Order, which continues to this day, with some 24 houses spread across the world.