In 1215 he was among the representatives sent to Otto of Brunswick along with Robert of Burgate. During King John's reign Robert is recorded as having witnessed 20 charters, an indication that he was at the kings side in intervals and he was an important member of John's court. Shortly after June 14th 1215 he had defected to the barons side in the Second Barons War despite his close relationship with king John. This was because he held some of his lands from or near rebels: William d'Albini of Belvoir and some lands in the richmong honour. Despite four letters offering safe conduct to Robert if he would rejoin the royal cause, he was a rebel through and through after 1215.