Reasons for Designation
An enclosure castle is a defended residence or stronghold, built mainly of
stone, in which the principal or sole defence comprises the walls and towers
bounding the site. Some form of keep may have stood within the enclosure but
this was not significant in defensive terms and served mainly to provide
accommodation. Larger sites might have more than one line of walling and there
are normally mural towers and gatehouses. Outside the walls a ditch, either
waterfilled or dry, crossed by bridges may be found. The first enclosure
castles were constructed at the time of the Norman Conquest. However, they
developed considerably in form during the 12th century when defensive
experience gained during the Crusades was applied to their design. The
majority of examples were constructed in the 13th century although a few were
built as late as the 14th century. Some represent reconstructions of earlier
medieval earthwork castles of the motte and bailey type, although others were
new creations. They provided strongly defended residences for the king or
leading families and occur in both urban and rural situations. Enclosure
castles are widely dispersed throughout England, with a slight concentration
in Kent and Sussex supporting a vulnerable coast, and a strong concentration
along the Welsh border where some of the best examples were built under Edward
I. They are rare nationally with only 126 recorded examples. Considerable
diversity of form is exhibited with no two examples being exactly alike. 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 educational resource, both with respect to medieval warfare and
defence and with respect to wider aspects of medieval society. All examples
retaining significant remains of medieval date are considered to be nationally
important.
Sleaford Castle is rare in being one of only three enclosure castles in
Lincolnshire, and one which was both constructed and maintained under
episcopal control. As a primarily administrative rather than military
establishment it includes examples of distinctive structures, such as
the manorial barn and constable's house, rarely associated with this type of
monument. The remains of the castle survive well as a series of substantial
earthworks and buried features which have never been excavated, suggesting
the survival of structural features, artefacts and ecofactual deposits; in
particular, waterlogging in the area of the moats will result in a high level
of survival for organic remains. Diverse features are evident which, as a
result of detailed historical research, are quite well understood. The remains
represent a limited period of occupation and are relatively undisturbed by
later activity; they will thus preserve valuable evidence for the construction
and use of the castle, and contribute to our knowledge of medieval society,
technology and economy. As a monument open to the public, Sleaford Castle also
serves as an important recreational and educational resource.
Details
The monument includes the remains of Sleaford Castle, an enclosure castle
built in the early 12th century by Alexander, Bishop of Lincoln. Following a
brief period of surrender to King Stephen in 1139 it was held by successive
bishops for over 400 years, serving as an administrative centre for the
episcopal estates in the Sleaford area. In the 15th century it was partially
rebuilt by Bishop Alnwick, and in 1547 was transferred by Bishop Holbeach to
Edward, Duke of Somerset. After this date it became a source of building
materials and was progressively dismantled. In 1720 parts of the walls and
towers were still standing; now the only fragment of masonry surviving above
ground is part of the north eastern corner tower. The monument includes the
standing remains of this tower and the earthworks and buried remains of the
remainder of the castle.
Sleaford Castle is situated on the edge of the medieval parish of New Sleaford
about 500m south west of the town centre. It is surrounded on all sides by
low lying land, formerly waterlogged, including part of Sleaford Fen. The
castle was built in this area of wet land by constructing raised earthwork
baileys surrounded by water channels. The remains of the castle take the form
of a series of substantial earthworks, including three raised areas: a large
L-shaped outer bailey which was defended solely by water; a quadrangular inner
bailey, defended by both water and a curtain wall; and a broad outer bank of
linear form. The earthwork remains of these features and the moats which
surrounded them occupy a roughly rectangular area on the south bank of the
Nine Foot River.
The outer bailey is approached from the north western corner of the monument
along a raised trackway, on the site of a former bridge, representing the
original entrance to the castle. The outer bailey, which is of L-shaped plan,
occupies the south western half of the monument; the western arm is
approximately 55m long, the southern 60m, and both are between 15m and 20m in
width. In the outer bailey are the earthwork and buried remains of
agricultural and domestic buildings associated with the castle's function as
the centre of a manorial estate. Principal among these are the remains of the
manorial barn, a large rectangular structure aligned roughly east-west in the
southern part of the bailey. The walls are visible as low earthworks defining
an area nearly 50m long and over 15m wide. Documentary sources of the 14th to
16th centuries record the storage here of produce from the episcopal estates.
Adjacent to the north east of the barn is a circular depression 1m deep
surrounded by buried walls 0.5m high; this is believed to represent the
remains of a circular dovecote, also known through documentary sources.
Attached to the west side of the barn are the buried foundations of a smaller
rectangular building approximately 20m long and 10m wide, believed to be the
remains of a byre. In the western part of the outer bailey are further slight
earthworks believed to represent the hall of the constable, who managed the
castle on behalf of the bishop, and associated outbuildings such as stables.
The outer bailey is surrounded by the remains of two moats which were fed from
the river to the north. On the south and west sides are the remains of the
outer moat, a linear depression up to 30m wide and 2m deep. It survives in
two parts: the southern arm, now dry, lies in the south eastern part of the
monument; the western arm, also dry, is now occupied by public play equipment
which is not included in the scheduling although the ground beneath it is
included. The two arms of the moat formerly met at the south western corner
of the outer bailey in an area outside the monument now occupied by the
railway. On the north east side of the outer bailey are the remains of the
castle's inner moat, also L-shaped. It is a dry, flat-bottomed depression up
to 20m in width. Both the outer and inner moats are linked on the north to the
earthwork remains of a further moat, constructed on the course of the river,
which survives as a dry depression about 10m wide and stands up to 1.5m above
the modern river channel which cuts along its northern edge. In the eastern
part of the monument the outer and inner moats are linked to a linear moat
aligned north-south, about 20m wide and still partially water filled, through
which they drained back into the river.
In the northern part of the monument, surrounded by moats, are the remains of
the castle's inner bailey. It is reached from the northern end of the outer
bailey by a raised trackway which crosses the inner moat on the site of a
former bridge. The inner bailey occupies a quadrangular area, approximately
80m by 60m, around the edge of which are the earthwork and buried remains of a
curtain wall; deep linear trenches indicate where the limestone was robbed for
reuse in the post-medieval period. In the north western part of the inner
bailey, at the approach from the outer bailey, are the remains of the outer
gatehouse, including two square depressions representing ground floor
chambers, one on each side of the curtain wall. The outer gate is known
through documentary sources to have had two portcullises. Also along the
curtain wall are the earthwork remains of mural towers; at the north eastern
corner is a large piece of standing masonry, partly fallen inwards and
supported by two concrete pillars, which has been interpreted as part of a
corner tower. The area enclosed by the curtain wall is divided into two
rectangular courts by the earthwork remains of a further wall, at the
north end of which are the earthworks of two substantial chambers, one on each
side of the wall; these are believed to represent the inner gatehouse, also
known through documentary sources. The area to the west of the dividing wall
is otherwise mainly level and represents an outer court, largely open apart
from some ancillary buildings such as the brewhouse. The area to the east of
the wall contains a substantial series of earth covered walls and partially
infilled depressions representing the remains of the main buildings of the
castle, including the keep and chapel, and their basement storage chambers.
On the eastern edge of the monument, separated from the inner bailey by a
moat, is a broad linear bank about 10m wide and 110m long. The top of the
bank is flat and stands about 1m above the moat on its western side and 2m
above the modern drain on the east. This bank, which forms an integral part
of the defended earthworks of the castle, is interpreted as the site of the
castle orchard or fruit garden described in documentary sources.
All fences and and posts are excluded from the scheduling although the ground
beneath them is included.
MAP EXTRACT
The site of the monument is shown on the attached map extract.
