The chronicler Symeon of Durham asserted that when St-Calais was consecrated bishop by Archbishop Thomas of York, he managed to avoid professing obedience to the archbishop, which, if true, would have freed St-Calais from interference in his diocese. After his appointment, St-Calais decided to replace his cathedral chapter of
secular clergy with monks, and consulted the king and
Lanfranc, the Archbishop of Canterbury, before going to Rome to receive permission from Pope
Gregory VII. These consultations, and the conditions within his diocese, may have kept St-Calais from visiting Durham until some time after his elevation. In 1083 he expelled the married clergy from the cathedral, and moved a small community of monks from
Bede's old monastery at
Jarrow to
Durham, to form the new chapter. This community had been founded at Jarrow by Reinfrid, a Norman ex-knight and monk of
Evesham Abbey, and Eadwine, an English monk from
Winchcombe Abbey. After the community had settled in Durham, St-Calais named Eadwine as
prior, and arranged for lands to be set aside to support the monks. After demolishing an Anglo-Saxon church, he and Prior
Turgot of Durham laid the foundation stone on 11 August 1093 for what would later become Durham Cathedral. St-Calais also gave a set of constitutions to the cathedral chapter, modeled on Lanfranc's rule for Canterbury. Symeon of Durham said that the bishop acted towards the monks of his chapter as a "loving father", and that the monks fully returned the sentiment. St-Calais is said to have researched the pre-
Norman Conquest customs of the cathedral exhaustively, before re-establishing monks in the cathedral. He imposed the
Monastic Constitutions of Lanfranc on the community, instead of the older
Regularis Concordia. ==Work for William the Conqueror==