Details

The monument includes a motte and bailey castle and is situated on a spur of
the North Downs above the Pilgrim's Way historic routeway. The motte takes
the form of a generally steeply-sided conical mound 70m in diameter at the
base with a flattened top 22m across. In a ring around the top of the motte
are traces of a shell keep, with one 2.5m section of flint walling more
prominent on the south-west side. On the western and northern sides the motte
drops some 5m to a ditch, now largely infilled by eroded soil from the mound,
which provided additional defence for the keep on the mound. This ditch, most
clearly visible for 150m to the NW of the motte, measures between 5m and 9m
in width and now reaches no more than 1m in depth. On the eastern and
southern sides the land slopes less steeply and the foot of the motte is
less clearly defined.
The bailey area to the west of the motte is defined by a thick flint wall,
much of which has been reduced to footings by robbing of the stone but which
survives to an impressive 3.5m in height along the northern edge. Integral to
this northern curtain wall, and beside the edge of the motte ditch, are the
remains of a gatehouse 10m long by 5.5m wide with blocked Norman-style
archways. The overall size of the bailey, as defined by the curtain wall, is
55m N-S by 35m E-W.
Beyond the curtain wall the land drops sharply to the road on the western
side. To the south, a quarry of uncertain date has undermined the boundary
wall. The quarry is likely to have had its origins in providing the flint
nodules for the building of the castle but is excluded from the scheduling.

MAP EXTRACT
The site of the monument is shown on the attached map extract.
It includes a 2 metre boundary around the archaeological features,
considered to be essential for the monument's support and preservation.

Source: Historic England

Reasons for Scheduling

Motte and bailey castles are medieval fortifications introduced into Britain
by the Normans. They comprised a large conical mound of earth or rubble, the
motte, surmounted by a palisade and a stone or timber tower. In a majority of
examples an embanked enclosure containing additional buildings, the bailey,
adjoined the motte. Motte castles and motte-and-bailey castles acted as
garrison forts during offensive military operations, as strongholds, and, in
many cases, as aristocratic residences and as centres of local or royal
administration. Built in towns, villages and open countryside, motte and
bailey castles generally occupied strategic positions dominating their
immediate locality and, as a result, are the most visually impressive
monuments of the early post-Conquest period surviving in the modern landscape.
Over 600 motte castles or motte-and-bailey castles are recorded nationally,
with examples known from most regions. As one of a restricted range of
recognised early post-Conquest monuments, they are particularly important for
the study of Norman Britain and the development of the feudal system. Although
many were occupied for only a short period of time, motte castles continued to
be built and occupied from the 11th to the 13th centuries, after which they
were superseded by other types of castle.

Thurnham Castle survives well and exhibits a wide diversity of features such
as the gatehouse and and stone built shell keep remains. It retains
considerable potential for the recovery of evidence of the nature and duration
of the use of the castle.

Source: Historic England

Sources

Other
SMR Ref No. TQ 85 NW,

Source: Historic England