Canterbury Castle


Heritage Category:
Scheduled Monument
List Entry Number:
Date first listed:
Date of most recent amendment:
Location Description:
Canterbury Castle lies on the south side of the old city within the old city walls, Canterbury, Kent.


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The building or site itself may lie within the boundary of more than one authority.

Location Description:
Canterbury Castle lies on the south side of the old city within the old city walls, Canterbury, Kent.
Canterbury (District Authority)
Non Civil Parish
National Grid Reference:


The scheduled monument includes the keep of the tower keep castle at Canterbury, part of its bailey, a sample of land just outside the bailey, the postern gate of the later enclosure castle and the castle and city ditch which originated in the Romano-British period.

Reasons for Designation

The tower keep castle known as Canterbury Castle is scheduled for the following principal reasons: * Rarity: as a tower keep castle it is a rare site type, there being only about 104 examples surviving nationally; * Period: it is an integral part of the development of the historic defended city of Canterbury locally and of the morphology of tower keep castles nationally; * Documentation: both the history of the castle and the history of archaeological investigation are well documented; * Potential: there is good archaeological potential remaining for future investigation; * Group value: the tower keep castle has group value with the adjacent motte-and-bailey castle known as the Dane John and with the abutting city walls; * Survival: the tower keep castle survives well and the bailey survives reasonably well.


Tower keep castles are strongly fortified residences in which the keep is the principal defensive structure which may be surrounded by a defended enclosure. Tower keep castles were a natural successor to motte and bailey castles, with the keep replacing the motte as the principal point of the castle. Although tower keeps are commonly square, cylindrical and polygonal examples are also found. The square or rectangular stone keep and its Romanesque style of architecture is particularly characteristic of the Norman period. The use of stone rather than the wood construction of the motte and bailey castle reduced the risk of fire and gave added strength, bringing with it the possibility of a taller construction and the advantage of wider visibility of the surrounding landscape. The notion that the keep was constructed principally to be a defensible place of last resort against attack is currently discredited in favour of broader interpretations which see towers as buildings which provided settings for ceremonial functions and, by virtue of their size, as landscape markers symbolising authority.

Tower keep castles were built throughout the medieval period from immediately after the Norman Conquest to the mid-C15. The White Tower in London, built in c1070, was one of the first constructed in this country, and indeed Caen stone from northern France used in The White Tower is the same type of stone as that used in the construction of Canterbury Castle. The high point of this type of building was c1125-1150. A variant on the tower keep is the hall keep where instead of a vertical arrangement the hall and chamber are side by side. The total number of tower keep castles is 104 of which 77 are true tower keeps and 27 hall keeps. Tower keep castles are distributed throughout England with a concentration on the Welsh border and into Wales.

The main component of a classic tower keep castle is a tower of several floors; the lowest being a basement with no windows and access only from the floor above. The entrance would have been at the first floor with access from external steps protected and enclosed by a forebuilding. The first floor would have internal staircases to the upper floors. This first floor typically served as the hall for retainers with the upper floor used as a chamber for the lord, above which was the roof and access to fighting platforms. In many cases the floors are divided into two by a cross wall or arcade. Fireplaces, latrines and well shafts would typically be present. The keep tower was surrounded by a stone-built enclosure or ward defended by curtain walls sometimes with mural towers. Within the ward there would be domestic or garrison structures which could not be fitted into the tower. These were originally of timber but were later rebuilt in stone. Such structures might include stables, workshops, a chapel, hall and kitchen. Beyond the curtain wall a ditch was commonly present.

Although many tower keep castles developed into enclosure castles (where the defensive function of the castle was assumed by the enclosure walls and towers), their defensive function largely ended with the development of artillery and they either fell into ruin or were slighted during the civil war of the C17, or continued in use as residences and/or administrative centres.

The tower keep castle at Canterbury Castle was begun by William the Conqueror in about 1085 as a replacement for the motte and bailey castle centred on the Dane John Mound (scheduled NHLE 1003780 and listed Grade II NHLE 1085047) which lies close by, about 235m ESE of the later castle keep. The tower keep was surrounded by a wall and ditch enclosing a bailey of about four acres. The south wall of the bailey reused part of the earlier C3 Roman town wall and also coincided with the later medieval city wall (scheduled separately NHLE 1003554). The junction between the bailey wall and the Roman City wall can be seen in a change of wall construction where the coursed mortared whole flints at the back of the Roman wall are interrupted by the closely set C19 knapped flints of the repair following the demolition of the bailey wall. There was a bridge and gate into the bailey at its north end with access to the city on the line that is now Castle Street, and a corresponding one in the south side of the bailey where it coincided with the city walls. The northern gate was the Great Gate and the gate in the bailey wall, which had been the Roman gate in the south west side of the Roman town walls, was called the Worth Gate. The Roman Worth Gate was reused in the medieval period but was demolished in 1791. The remains of the Worth Gate and part of the city wall are incorporated into No 28 Castle Street (listed Grade II NHLE 1085095)

The keep was largely built in the reign of Henry I (1100-1135) as one of three Royal castles in Kent (the others being Rochester and Dover). Henry II (1154-1189) increased the extent of the castle and its fortifications by exchanging land elsewhere in Canterbury for land in the vicinity of the castle and also made repairs to the castle between 1173 and 1174. Repairs were made again between 1190 and 1193 in the reign of Richard I (1189-1199).

NOTABLE EVENTS The castle saw action several times and was involved in a number of notable events in English history: it surrendered to the Barons in the reign of King John (1199-1216); during the reign of Henry III (1216-1272) it was under the custody of Hubert de Burgh, Earl of Kent, when it was taken by the French. The French had landed at the Isle of Thanet and Sandwich and embarked on a campaign in the area (1215-1217) at the time of the disputed claim to the throne of England by Louis VIII of France. It was also captured by the rebels in Wat Tyler’s rebellion of 1381.

USE AS A PRISON Apart from its defensive role, the castle was also used as a centre of administration by the sheriff, and, from about 1293, as a prison. The gaol at the castle had been in existence since the time of Edward I (1272-1307) when it was used for mass imprisonment and continued in use through to the time of Queen Mary (1553-1558) who employed it in connection with religious persecution until it was replaced by the Westgate (scheduled NHLE 1003554 and listed Grade I NHLE 1241660) in 1577.

LATER HISTORY By 1335 the castle was largely in ruins. The ruined castle was in royal hands until the early C17 when it was owned successively by a number of individuals. The castle walls and gate were demolished in 1791-2. The keep which now stands to two storeys high was reduced in height in 1817. The medieval topography of the area of the castle has been gradually reduced since the early C19. The gas company bought the keep in 1826, the water works also moved into the area and the tower was used as a coal store. The castle was finally purchased by Canterbury City Council in 1928.

Now only the ruins of the square keep and a small part of the bailey wall dating to about 1085 are left extant. Canterbury Castle was scheduled on 9 April 1915 and was listed Grade II on 3 December 1949 (the city wall which is on the line of the south bailey wall is scheduled separately as NHLE 1003554).

In the C19 and C20 the area which was formerly the castle bailey was partially occupied by the gas works, and other assocaited buildings. This area was, no doubt, damaged when the southern part of Canterbury was bombed during WWII in the Baedeker Raids of 31 May and 6-7 June 1942. These raids, named after the Baedeker travel guide books which the Germans used to identify their targets, were carried out on historic English cities in retaliation for the allied bombing of Lubeck on 28 March 1942. In any case open areas were created here by post-1945 clearance of C19 and earlier buildings. The western side of Castle Street was redeveloped as a multi storey car park but the eastern side remains (2014) as an open area car park with the exception of the Age Concern building.

EXCAVATION HISTORY There is a long history of excavation concerned with the castle, much of which was instigated by the Canterbury Archaeological Society and the Canterbury Archaeological Trust. This work followed on from discoveries made in the C19. In the present era the main planned excavations were in 1939 when Dr G Webster investigated the SE side of the keep; in 1953 and 1955 Professor SS Frere excavated the keep and the area towards the city wall. In 1971 Miss L Millard excavated the foundations of the original entrance to the keep and in 1975 to 1977 the Trust excavated to the west of the keep and the Rosemary Street car park to the north of the keep.

EARLIER HISTORY There is evidence for both Romano-British and Saxon presence in the area of the castle and bailey. The 1953 excavations by the Canterbury Archaeological Trust directed by Professor Frere, within and immediately outside the keep and beneath the medieval horizon, found evidence of late C2 or C3 occupation but no structures. In addition Saxon rubbish pits were discovered. Saxon evidence continues through to the city wall to the SE of the keep where C9 rubbish pits and a Saxon road were found overlying the Roman rampart. To the east of the keep in what is now the Castle Street car park there is evidence for Romano-British burials in the form of mortuary urns, one containing ashes, bone and pins. Excavations in 1976-1977 by Paul Bennett to the north of Gas Lane discovered evidence of occupation from the mid C1 which included a ditch of possibly military origin. Excavations in 1975 to the west of the keep, south of Gas Lane, found a mixed layer containing Romano-British building debris, indicating a building in the vicinity, and late Roman coins.


The castle lies in what was the south part of the city; the southern bailey wall, built on the line of the earlier Roman town wall, became part of the medieval city wall. The city wall is separately scheduled (NHLE 1003554).

The keep, which measures 26m by 30m externally, has walls which are 2.7m thick. It comprises a thick (4m) rubble flint plinth at its base with bands of flint and Caen stone blocks above. There is no evidence that the plinth was faced in Caen stone blocks, but they may have been robbed out. The keep stands now to about 20m high and its square form denotes its Norman origin. It has buttresses clasping the angles and on the sides: one on each of the shorter sides and two on each of the longer sides. The keep originally had four round arched windows on each side, although because of its ruinous state not all survive. The interior has two cross walls and the remains of spiral staircases in the E and SW walls. Fireplaces composed of rubble set in herringbone pattern survive, set into the walls. There were at least three floors, marked by substantial beam-holes, though only beam-holes for the first floor survive. The upper floor has largely gone.

The keep, which is of typical Norman construction, originally had a first floor entrance via a forebuilding. The 1971 excavations on the west side of the keep by Miss L Millard with the Canterbury Archaeological Society located the foundations of this original entrance with its forebuilding. On the SE side of the keep excavation by Dr G Webster in 1939 showed that there was a later modification in the form of a probable C13 to C14 entrance with two round towers leading to a ground floor entrance.

The keep lies towards the SW side of the inner bailey. The only surface indications of the bailey wall and ditch is a ‘break in slope’ of the ground surface behind the oast house to the south of Gas Lane on the W side of the keep. However the buried remains of this bailey ditch and wall continue southwards towards the city wall. Also to the W of the keep, to the S of St Mildred’s church yard, is the site of a postern gate (one of three medieval posterns in the city walls) which is depicted in a pen and ink drawing of 1757 by Jonathan Skelton (c 1735-1759) and is in the Whitworth Art Gallery in Manchester. To the W of the bailey ditch is a grassed area. A trial trench dug in this vicinity in 1975 by Mrs P Garrard produced a number of pits and ditches. It was also shown that the area contained a sealed layer of plough soil indicating arable land use immediately outside the inner bailey after the castle was built. To the N of the keep beneath Gas Street is a further part of the inner bailey and a continuation of the bailey wall and ditch.

The area to the NNE of the Keep, where the archaeological stratigraphy is not destroyed by the Rosemary Lane car park and the make up of Castle Street, also contains part of the inner bailey, bailey wall and ditch and the remains of the Great Gate. The bailey and its defences extend into the land which is now Castle Street car park. Here finds of Romano-British mortuary urns indicate earlier use of the area.

The bailey and its defences extend S to the city walls (scheduled separately – see above). Here there are the buried and extant remains of the Romano-British Worth Gate which became the castle gate in the medieval period. On the S side of the scheduled city wall is the buried remains of the substantial Romano-British ditch which was also reused in the medieval period. This has been compromised by the construction of Rheims Way and the pedestrian underpass to the W of Castle Street but will survive to the E in the areas not affected by house cellars.

EXTENT OF SCHEDULING The scheduling aims to protect the tower keep castle including the keep, the surviving parts of the bailey and its ditch including a sample beyond the city wall. The maximum extent of the scheduling is about 165m NW-SE by about 106m NE-SW.

EXCLUSIONS A number of buildings and features are excluded from the scheduling; these include the Oasthouse and its adjoining building, No 28 Castle Street (Castle House) although the adjoining remains of the Romano-British Worthgate are included, 39 Castle Street, the buildings and structures in Castle Street car park including the Age Concern building; all wooden platform walk ways inside the keep, notice and information boards, service pipes and wiring, boundary walls and railings, paths, roads, tarmac hard surfaces and their makeup. However, the ground beneath all of the above features is included.


The contents of this record have been generated from a legacy data system.

Legacy System number:
KE 1
Legacy System:


Books and journals
Bennett, P et al, The Archaeology of Canterbury Vol 1, (1982), 19-88
Canterbury Castle, accessed from
Canterbury Castle, accessed from
Canterbury Castle, accessed from


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

End of official listing