Research Notes:

Roger de Mortemer was related to the Warenne family but the precise relationship has not been determined.... Orderic Vitalis records that "Roberti Aucensis comiitis et Rogerii de Mortuomari" led the Norman forces ("Caletorum catervam" = troops from the pays de Caux) who defeated Eudes, brother of Henri I King of France ("Odonem fratrem suum") "apud Mortuum-mare" in 1054. In a later passage, recounting a death-bed speech of William I King of England, the same source records that "Rogerium de Mortuomari et omnes Caletenses" had defeated the French troops "apud Mortuum-Mare" but that "Rogerius princeps" helped the escape of "Rodulfus…comes" (identified more precisely in another passage as "Radulfum comitem de Monte-Desiderii") to whom he had done homage, for which treachery Roger was exiled and his lands confiscated, including "castrum…Mortui Mari" which was granted to "Guillelmo de Guarenna consanguineo eius". The Brevis Relatio de Origine Willelmi Conquestoris records that "Rogero de Mortuomari" contributed 120 ships towards the invasion of England in 1066, which suggests that he had been fully reconciled with the future William I King of England by that time. He acquired land at Wigmore which had been forfeited by Roger Earl of Hereford in 1075. "…Rotberto de Bello Monte, Henrici de Bello Monte, Rotberti Gifordi, Rogerii de Mortuo Mari, Goiffridi de Calvo Monte, Radulfi dapiferi, Mauricii cancellarii, Willelmi de Warenna, Gundrede uxoris W. de Warenna" subscribed the undated charter under which William I King of England confirmed the donation by William de Warenne of the church of St Pancras to the monastery of Cluny, dated to [1078/81] by the Complete Peerage.

Roger is not named in Domesday Book in 1086. ¹