In 1088 Rochester Castle came under attack during the conflict between William Rufus and Odo the bishop of Bayeux. In 1087, after William the Conqueror had died, control of Normandy was disputed. Odo, along with many others, supported William's elder brother Robert, Duke of Normandy, while others supported William Rufus, the Conqueror's younger brother. Odo had control of Rochester Castle and it became the headquarters for the rebels. The castle fell to William Rufus' army and Odo was forced into exile. Gundulf, the bishop of Rochester, orchestrated the construction of a stone castle alongside the Norman cathedral. King Henry I granted the castle of the bishops of Canterbury and in 1126 the construction of a new large keep was begun by William de Corbeil, the Archbishop of Canterbury. Over the centuries the castle was the scene of many conflicts including King John's attempt to regain the castle from the Barons and in 1264 Simon de Montfort's rebellion. It was during King John's siege of the castle that undermining brought down one of the southern corners of the keep. The destroyed corner tower was later rebuilt.
Gundulf used existing sections of Roman walls in the construction of Rochester Castle. These were repaired and their height increased. New walls were constructed to enclose a large bailey with a ditch on the outside. Not much of Gundulf's original castle survives as it was rebuilt by William de Corbeil, Archbishop of Canterbury, sometime after 1126. At 125 feet high the keep he built at Rochester is the tallest in England. The keep has a square ground plan and has four corner towers that project slightly. On three of the four faces of the keep are pilaster buttresses at the centre and at each end of the walls. The north-east face having two buttresses.
Entrance to the Keep
Access to the keep is via a series of steps along the north-west and north-east sides. A square tower or forebuilding originally protected these steps but it has been demolished. A drawbridge separated the forebuilding from the entrance to the keep for extra protection. Directly inside the keep is a lobby where guards would have positioned. To the right of the main entrance is the door to the keep and in this doorway are slots for a portcullis. The lobby is lit by three small typical Norman round-headed windows. Below the lobby are two floors of rooms for storage or possibly a dungeon and above it is the chapel.
The castle is divided into two halves by a central wall oriented north-west to south-east. This central wall has a central well-shaft so that water could be accessed from each floor. The central wall supported two low-pitched rooves. A large spiral staircase can be found in the eastern tower of the keep that is used to access all floors from the basement to the wallwalks. A similar staircase in the western tower starts from the first floor and reaches to the top. The ground floor was most likely used for storage. The main hall of the keep is on the second floor and on this floor the central dividing wall is pierced by an arcade of columns with round-headed arches decorated in typical cheveron designs. The hall floor is very high and has a barrel-vaulted gallery running around the top, both providing extra light and somewhere to watch proceedings from.