Reasons for Designation
A shell keep castle is a masonry enclosure, extending around the top of an
earlier motte or castle ringwork, and replacing the existing timber palisades;
there are a few cases where the wall is built lower down the slope or even at
the bottom. The enclosure is usually rounded or sub-rounded but other shapes
are also known. A shell keep is relatively small, normally between 15 and 25m
diameter, with few buildings, and perhaps one tower only, within its interior.
Shell keeps were built over a period of about 150 years, from not long after
the Norman Conquest until the mid-13th century; most were built in the 12th
century. They provided strongly fortified residences for the king or leading
families and occur in both urban and rural situations.
Shell keep castles are widely dispersed throughout England with a marked
concentration in the Welsh Marches. The distribution also extends into Wales
and to a lesser extent into Scotland. They are rare nationally with only 71
recorded examples. Considerable diversity of form is exhibited with no two
examples being exactly alike. Along with other castle types, they are major
medieval monument types which, belonging to the highest levels of society,
frequently acted as major administrative centres and formed the foci for
developing settlement patterns. Castles generally provide an emotive and
evocative link to the past and can provide a valuable education resource, both
with respect to medieval warfare and defence, and to wider aspects of medieval
society. All examples retaining significant remains of medieval date are
considered to be nationally important.
The earthworks of Castle Acre Castle have been described as being among the
finest surviving in England, and the complex sequence of development revealed
in the excavations in the upper ward is in some respects, and so far as is
known, unique. The size of the castle and the grand scale of the buildings
within it reflect the power and wealth of the de Warenne earls who were, in
the 11th and 12th centuries, among the leading magnates in the country under
the king. The amount of archaeological evidence recovered during the limited
excavations is indicative of what is likely to be preserved in the remainder
of the castle, which will retain much additional information relating to the
construction and development of the lower ward, its defences and the buildings
within it, and to the later use of the castle. The infilled ditch around the
southern end of the lower ward is likely, in addition, to contain waterlogged
deposits in which organic materials, including evidence for the local
environment during the medieval period, is likely to be preserved. The
excavations have also demonstrated that evidence for earlier occupation of the
site, predating the construction of the castle, is contained in the buried
soils beneath the 11th and 12th century earthworks. The direct archaeological
and historical association between the castle, the 12th century planned town
and the priory (also founded by the de Warennes) which lies to the west, give
the monument additional interest. As a monument in the care of the Secretary
of State, maintained for public display, the castle is also a valuable
educational and recreational amenity.
The planned town is one of several established in Norfolk and, because it has
been affected very little by later development, the principal elements of the
original layout remain clearly apparent. The survival of much of the
surrounding ditch and part of the bank as visible earthworks, and of the north
gate of the town, are especially worthy of note.
Details
The monument includes the earthworks and other structural remains of Castle
Acre Castle, the remains of the defensive works which enclosed the area of the
Norman town to the west of the castle, and the gatehouse which guarded the
northern entry to the town. These features are located in the southern part of
the modern village of Castle Acre, on the northern slope of the valley of the
River Nar, above the point where the river is crossed by the Peddars Way.
The visible remains of the castle, which are Listed Grade I and are in the
care of the Secretary of State, include a roughly circular upper ward, with an
adjoining, sub-rectangular lower ward on the south east side and a roughly
triangular barbican (defensive outwork) to the east. The upper ward is
surrounded by a deep ditch, now partly infilled but still open to a depth of
3m-4m, and an inner bank surmounted by a curtain wall, and contains the
standing ruins of a massive masonry building, with buried remains of
associated, less substantial buildings. The outer ward is also surrounded by
a ditch, with internal banks on the east and west sides, and fragmentary
remains of a wall crowning the banks and closing the southern end. On the
south side of the upper ward are the remains of a gatehouse which guarded the
entry from the lower ward, and there are remains of two other gatehouses,
sited at the junctions between the defences of the upper and lower wards on
the east and west sides and giving access to the lower ward from the barbican
and town respectively.
The walls of the main building in the upper ward, exposed and consolidated
after part excavation between 1971 and 1977, display evidence of two major
alterations, and limited investigation of the defences surrounding it have
shown that these, also, were strengthened and enlarged twice. The original
building, which is dated to the later 11th century and was probably
constructed soon after the Conquest of 1066, was a strong hall, square in plan
and of two storeys, divided by an internal east-west spine wall. The outer
walls, approximately 2m thick at the base and constructed of mortared chalk
rubble faced with flint, contain the remains of blocked, single light windows
to the east and west and a blocked door opening at ground floor level in the
south wall, as well as internal features such as a chimney flue in the north
wall, and sockets for the joists to support the upper floor. Two small masonry
buildings, no longer visible, abutted the outer face of the north wall. The
house and associated structures stood within a courtyard surrounded by a ditch
and an internal bank 3.3m high which survives as a buried feature beneath the
later earthworks. The bank probably supported a timber palisade but was not
strongly defensive. The gatehouse on the south side of the upper ward was
inserted into the inner bank to replace an earlier timber structure, evidence
for which was observed in excavation. It is rectangular in plan, with inner
and outer openings, and the surviving walls are constructed of mortared chalk
rubble. Part of the springing of the round-headed inner gate arch is preserved
on the west side.
The major alterations to the house are dated to around 1140, during the
`anarchy' of the reign of King Stephen and were designed to convert the
building into a keep. The ground floor openings in the outer walls were
blocked and the walls themselves were doubled in thickness by the addition of
a masonry lining abutting their inner face. The straight junction between the
two is still clearly visible. Two well shafts are incorporated within the
thickness of the lining walls at the north east and south east angles. During
this conversion, the ground floor level was made up to approximately its
present height by the dumping of soil and chalk rubble to a depth of
approximately 1m. Subsequently, in a second major alteration to the building,
the walls of the southern half were demolished to ground level, and the spine
wall was strengthened and refaced on the outer side to form the southern wall
of the reduced keep, which still stands to a maximum height of about 8m.
The associated strengthening of the surrounding defences included, in the
first stage, the enlargement of the ditch, the raising of the bank by
approximately 2m, and the construction of a curtain wall of chalk rubble faced
with flint. In the second stage, which probably followed the reduction in size
of the keep, the bank on the north side of the ward was further raised to its
present height of up to 9.5m above the original ground surface, and the height
of the curtain wall on that side was also increased by building on to the
existing masonry. Although the wall on the east side of the ward is very
ruinous, and in places only the footings survive, parts on the north and north
west side still stand to the height of the parapet walk, and the difference in
height and construction between the original wall on the south side and the
augmented wall to the north remains apparent. In addition to part of the
parapet walk, the wall to the north displays the remains of other original
features, including buttresses on the outer face and a diagonal vaulted
passage through it, perhaps to an external tower or postern. The tail of the
enlarged bank encroached on the interior of the ward, raising the ground
surface on the north side to the height of the first floor of the keep and on
the south side to a somewhat lower level. Excavation of this surface to the
west and north west of the keep uncovered the flint rubble footings for timber
framed buildings against the inner face of the curtain wall. Modifications of
the gatehouse associated with the later fortification included the raising of
the outer threshold and the partial blocking of the gate arches so as to
narrow the entry.
The remains of the western and eastern gatehouses to the lower ward are also
exposed, together with the footings of parts of the curtain walls linking them
to the wall around the upper ward to the north. The ruined walls of the
western gatehouse include the bases of twin drum towers on the outer, western
face, and the remains of door openings on either side of the gate passage. The
freestone sills and parts of the lower jambs of these doors survive, with some
of the original ashlar facing at the base of the passage walls, including
parts of the rebates for double doors in the inner and outer gate openings,
and of grooves for a portcullis. Slots for draw bars are also visible in the
rubble core of the northern wall above this level. The door on the south side
of the gate passage opens into a partly excavated chamber beneath the
adjoining bank of the lower ward, and the door on the north side into a small
rectangular chamber outlined by wall footings. Adjoining the outer face of the
north wall of this chamber is the base of a garderobe (latrine) shaft from a
now vanished upper floor. The eastern gatehouse is less well preserved, but
the remains are sufficient to show that it was a less elaborate structure.
Excavations in the ditches opposite the eastern gatehouse and the gatehouse of
the upper ward revealed evidence for timber bridges, now replaced by modern
structures which are not included in the scheduling.
The barbican, which guarded the eastern gate to the lower ward, is protected
by a substantial ditch and inner bank, and a gap in these earthworks on the
eastern side marks what is thought to be the original entry. Adjoining the gap
is a low, sub-rectangular earthwork which probably marks the site of the gate.
A length of masonry across the ditch at the southern end is all that remains
visible of the wall which would originally have stood on the earthworks and
linked with the curtain walls of the upper and lower wards, but further
evidence for this is likely to survive beneath the surface of the bank, which
has not been investigated.
The earthworks of the lower ward are on a similar scale to those of the upper
ward. The foundations of the curtain wall are visible in places on the surface
of the banks, and part of it still stands to a height of up to 7m on the west
side. Another length of wall, faced externally with coursed flint and
including a rectangular opening, stands across the southern end of the
enclosure. Here the bank is very slight, but immediately to the south of the
wall is a steep scarp above the flood plain of the river. The ditch at the
foot of the scarp has become completely infilled and is no longer visible, but
limited excavations prior to the installation of a sewer in 1987 have
confirmed that it survives as a buried feature and was at one time water-
filled.
Within the lower ward, the outlines of three buildings are clearly defined by
turf-covered wall footings. The largest, in the middle of the enclosure, is a
rectangular great hall, aligned on an east-west axis, with a solar (private
apartment) at the eastern end. A much smaller, square building to the west of
this was probably a detached kitchen, and another rectangular building to the
north was perhaps a chapel. The hall was almost certainly built to replace the
house in the upper ward, after the conversion of the latter to a keep.
Evidence for other, less substantial structures, including service buildings
and stables, is likely to survive beneath the ground surface.
At the time of the Domesday survey in 1086, Castle Acre was held by William
de Warenne, first Earl of Surrey (died 1088), who is thought to have been
responsible for the building of the original, lightly defended house (domus
defensabilis). The conversion of the house to a strong castle took place
either during the time of his son (died 1138) or, more probably, his grandson
(died 1148). Throughout the 12th and 13th centuries the castle continued to be
an important administrative centre, and visits by King Henry III and his son
Edward I are recorded, but during the 14th century it was neglected, and an
inquisition on the estate of Richard Earl of Arundel, executed for treason in
1397, recorded the value of the castle as nil, indicating that by then it was
derelict. The estate, including the castle, was eventually acquired by Sir
Edward Coke in 1615.
The Norman planned town occupied a rectangular area some 4.25ha in extent
(approximately 225m north-south by 188m east-west) immediately to the west of
the castle. It was enclosed by a ditch and an internal bank surmounted by a
wall, with gates on the north and south sides, and the remains of these
defences are included in the scheduling. The bank and ditch on the west side
and along much of the south side survive as substantial earthworks, known as
Dyke Hills. The ditch is approximately 17m wide and remains open to a depth of
approximately 3m, and the bank stands to a height of up to 3m. On the south
side, where the ground slopes steeply down to the river, the bank decreases in
height and disappears towards the eastern end, and the ditch immediately to
the west of Bailey Street appears as a steep, south-facing scarp above a
slight depression in the ground surface. Immediately to the east of Bailey
Street, the ditch has been largely infilled, although the inner edge remains
visible as a slight scarp and the rest will survive as a buried feature. The
eastern end originally abutted the castle ditch at the southern end of the
outer ward, but this section has been removed by a later quarry. The
earthworks along the northern side have been levelled, but evidence recorded
during installation of sewers has confirmed that the ditch survives as a
buried feature beneath Stocks Green and the High Street and, at the eastern
end, the inner edge of the ditch and traces of the outer edge can still be
traced, curving southwards to meet the ditch around the inner ward of the
castle. Little remains standing of the town wall except the eastern end on the
south side, blocking the castle ditch, but other remains, including
foundations, are likely to be preserved below the surface of the bank around
the western side.
Broken stubs of the wall can also be seen on the eastern side of the partly
ruined northern gate, known as the Bailey Gate, which stands at the northern
end of Bailey Street. This is massively built of mortared flint with stone
dressings and, although now roofless, still stands to full height, with twin
drum towers fronting recessed inner and outer arches. On the inner faces of
the walls are remains of the slots for a portcullis. The lower end of Bailey
Street is a well-developed hollow way. Where it crosses the line of the wall,
it is possible that evidence for the southern gate survives below the ground
surface.
The houses and associated garages and outbuildings which stand above the
buried section of the town ditch are excluded from the scheduling, together
with all modern fences and gates, garden walling and paving, garden
furniture, English Heritage signs and information boards, modern wooden
bridges across the castle ditches, the surfaces of modern roads, driveways,
paths and the visitor car park adjacent to the castle earthworks, street
furniture, a transformer on the south side of the southern arm of the town
ditch, service poles, and inspection chambers, although the ground beneath all
these features is included.
MAP EXTRACT
The site of the monument is shown on the attached map extract.
