A contemporary record of this trial, the De Iniusta Vexacione Willelmi episcopi, is the earliest surviving detailed contemporary report of an English state-trial. Imprisoned briefly, St-Calais was allowed to go into exile after his castle at Durham was surrendered to the king. He went to Normandy, where he became a leading advisor to Robert Curthose, Duke of Normandy, the elder brother of William Rufus. By 1091, St-Calais had returned to England and regained royal favour.
In England, St-Calais once more became a leading advisor to the king. In 1093 he negotiated with Anselm, Abbot of Bec, concerning Anselm's becoming Archbishop of Canterbury; in 1095 it was St-Calais who prosecuted the royal case against Anselm after he had become archbishop. During his bishopric, St-Calais stocked the cathedral library with books, especially canon law texts. He was also active in defending the north of England against Scots raids. Before his death, he had made his peace with Anselm, who blessed and consoled St-Calais on his deathbed.