[4] The story that he became William's chancellor is based entirely on a charter that modern historians have declared mostly spurious.
[3] He became Bishop of Exeter in 1072,[5] and was consecrated at St. Paul's in London on 27 May 1072 by the Archbishop of Canterbury, Lanfranc.
[3] Osbern was present at the first Christmas court held by King William II of England after his accession.
[6] Osbern did not attend the church council held by Anselm, the new Archbishop of Canterbury in 1102, as he was ill.[7] Osbern became embroiled in a dispute with the monks of Battle Abbey, who had established a priory in Exeter.
Their father was Osbern de Crépon, a guardian and seneschal to the young Duke William.