White Tower
The White Tower is a keep (also known as a donjon),which was often the strongest structure in a medieval castle, and contained lodgings suitable for the lord – in this case the king or his representative. According to military historian Allen Brown, "The great tower [White Tower] was also, by virtue of its strength, majesty and lordly accommodation, the donjon par excellence".As one of the largest keeps in the Christian world, the White Tower has been described as "the most complete eleventh-century palace in Europe".
The White Tower, not including its projecting corner towers, measures 36 by 32 metres (118 by 105 ft) at the base, and is 27 m (90 ft) high at the southern battlements. The structure was originally three storeys high, comprising a basement floor, an entrance level, and an upper floor. The entrance, as is usual in Norman keeps, was above ground, in this case on the south face, and accessed via a wooden staircase which could be removed in the event of an attack. It was probably during Henry II's reign (1154–1189) that a forebuilding was added to the south side of the tower to provide extra defences to the entrance, but it has not survived. Each floor was divided into three chambers, the largest in the west, a smaller room in the north-east, and the chapel taking up the entrance and upper floors of the south-east. At the western corners of the building are square towers, while to the north-east a round tower houses a spiral staircase. At the south-east corner there is a larger semi-circular projection which accommodates the apse of the chapel. As the building was intended to be a comfortable residence as well as a stronghold, latrines were built into the walls, and four fireplaces provided warmth.]
The entrance floor was probably intended for the use of the Constable of the Tower, Lieutenant of the Tower of London and other important officials. The south entrance was blocked during the 17th century, and not reopened until 1973. Those heading to the upper floor had to pass through a smaller chamber to the east, also connected to the entrance floor. The crypt of St John's Chapeloccupied the south-east corner and was accessible only from the eastern chamber. There is a recess in the north wall of the crypt; according to Geoffrey Parnell, Keeper of the Tower History at the Royal Armouries, "the windowless form and restricted access, suggest that it was designed as a strong-room for safekeeping of royal treasures and important documents".
The upper floor contained a grand hall in the west and residential chamber in the east