Note 178 — Chapter VI · THE KEEP OF THE NORMAN CASTLE
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This points to two separate dates for the structure. The earlier masonry has been attributed to Bishop Flambard, who founded the castle in 1121; the later to Bishop Pudsey, who made additions to the castle about 1157. If this is so, the history of the tower is parallel to that of Porchester—a low stone tower, possibly of the reign of Henry I., heightened in the reign of Henry II.