Note 1141 — Chapter XII · STONE CASTLES OF THE NORMAN PERIOD

Piper states that the evidence of remains proves that the lower storey was a prison. But these remains probably belong to a later date, when the donjon had been abandoned as a residence, and was becoming the dungeon to which prisoners were committed. The top storey of the keep was often used in early times as a prison for important offenders, such as Conan of Rouen, William, the brother of Duke Richard II., and Ranulf Flambard.