Francis Blomefield,
History of Norfolk — Chapter 11
“ In 1212, Roger Bigot Earl of Norfolk attended the King into Poictou; but afterwards, in 1215, he sided with the rebellious Barons, against their prince, upon which the castle was seized, and William Marshall Earl of Pembrook, being then associated with John FitzRobert in the sheriffalty of Norfolk and Suffolk, were by patent made constables of the castles of Norwich and Orford in Suffolk, but were soon discharged of those trusts ”
