Details

This unusual motte and bailey castle occupies a low-lying area at the former
confluence of the Rivers Uck and Ouse. It comprises a low mound or motte
surrounded by a circular moat, a ditch leading eastward from the moat,
another dog-legged ditch leading north-eastwards and a broad east-west ditch
and bank defining the northern edge.
The site was made defensible by the diversion of the River Ouse and the
creation of an island 200m by 112m on which the castle was located. This
diversion involved the digging of a channel 13m wide between two natural
meanders of the rivers on the NE and NW sides. Within the island, another
channel was cut taking water from the Ouse around the circular motte and
out to rejoin the main stream of the river. In so doing, the island was
raised above the level of the floodplain and was divided into a western
inner bailey and an eastern, much larger, outer bailey. The central feature
of the castle was the motte, which measures 22m in diameter and is raised
1.4m above the level of the surrounding land, or 3m above the base of the
surrounding moat. The motte is stepped on the eastern and southern sides
owing to a landslip in relatively recent times.
On the southern edge of the castle is the site of a rectangular fishpond,
23m by 10m in size and with a drainage leat on the SW side. The dog-legged
ditch is interpreted as a later addition to the monument since it is both
deeper and more steeply embanked than the other channels. Its purpose is
unclear, but it may be connected with the artificial lake created to the
north, to which the 1.6m high bank alongside the east-west channel belongs.
The post and wire fencing around the site 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.

The example at Isfield is unusual in its lowland siting. It illustrates an
alternative defensive strategy to the high motte and, because of the absence
of later disturbance of the site, it retains high archaeological potential.

Source: Historic England

Sources

Books and journals
Hope-Taylor, B, 'Archaeological Journal' in Excavation Of A Motte At Abinger In Surrey, , Vol. 107, (1950), 15-43
Montgomerie, D H, 'Sussex Arch Collections' in , , Vol. 75, (1934), 207-8
Other
Dennison, E., MPP Single Monument Class Descriptions - Fishponds, (1988)
Motte and bailey classification, Leach PE, Motte and Bailey Castles, Monument Class Description, (1988)
TQ41 NW1,

Source: Historic England