| Summary : A medieval motte and bailey castle constructed within an Iron Age enclosure (TL 88 SE 123). The castle is believed to have been constructed shortly after the Norman Conquest, either by Ralph Guader, Earl of East Anglia until his rebellion in 1076, or Roger Bigod, his successor as Earl. It was sited in a position to control important crossings of the rivers Thet and Ouse, as well as to dominate the town of Thetford which, at the time of the Domesday survey in the late 11th century, was among the six largest and most populous towns in the country. The motte is a large, circular mound of chalk, approximately 25 metres in height and 90 metres in diameter surrounded by a bank of chalk rubble 2 metres in height. The platform would have supported a timber tower, evidence for which will survive below the ground surface, and it is likely that the bank represents the footing of a wall or timber palisade. The base of the motte is encircled by a ditch about 18-20 metres wide which remains open to a depth of between 5 metres and 6 metres, and enclosing this on the north side is a very large double bank and ditch. Immediately to the east of the motte and its encircling ditch is an area of level, open ground bounded on the north side by a double bank and ditch which are contiguous with the earthworks to the north of the motte. A sketch plan of the earthworks drawn in the first half of the 18th century shows the inner bank extending east of Castle Lane and turning southwards to enclose a sub-rectangular bailey with estimated dimensions of about 105 metres WNW-ESE by up to 90 metres. This eastern part of the bank is no longer visible, having been levelled in 1772. The surviving inner bank on the north side of the bailey stands to a height of about 6 metres above the prevailing ground surface and the inner ditch remains open to a depth of 10 metres from the top of the bank. Scheduled. |
More information : [TL 87398282] Castle Hill [G.T.].(1)
Evidently a motte and bailey castle with a motte 80 ft. high and nearly 1,000 ft. in circumference, and one of the largest in England. Baillie Reynolds supposes it was made by Roger Bigod, to whom William the Conqueror assigned this part of the country. According to a pipe-roll for 19 Henry II, 1172-3, the castle had then recently been demolished. (2)
Excavations for the Norfolk Research Committee showed that in the late 11th century a motte with its own ditch was constructed in the W. part of an Iron Age fort, with much of the I.A. banks and ditches having been destroyed. Cuttings in the inner bailey revealed pottery and other objects ranging from the late 11th to the mid-13th centuries. Beaker pottery and an Early Bronze Age flint arrowhead were found.
An outer bailey added to the N. side of the earthwork contained a number of sub-oval foundations of chalk rubble, unconfirmed in date but probably connected in some way with the medieval castle.(3-4)
This earthwork appears to have originally comprised an Iron Age 'Promontory' Fort consisting of a double bank and ditch isolating the land in a south bend of the River Thet. At the east end the banks terminate on an area of marshy ground but at the west end they have been destroyed by the development of the town, but clearly ran down to the river or its flood plain.
The I.A. defences were later modified into the inner bailey attached to a motte which was constructed in the northern part of the I.A. fort. The motte stands up to about 25.0m. in height, is 90.0m. in diameter at the base and 26.0m. in diameter at the summit. It is surmounted by a small circular bank.
A small bank some 8.0m. in width and up to 1.0m. high runs alongside the south side of Ridge Road. It is possibly the outer bailey noted by Clarke and Green but it is rather small. Published 1/2500 survey revised. See Illustrations Card.(5)
(TL 87398282) Castle Hill (NAT) Motte & Bailey (NR). (6)TL 87398282) Castle Hill (NR). (7)
TL 875828. Thetford castle is essentially a very large and strong motte built within an Iron Age bivallate enclosure, which served as a bailey. The castle is probably a royal work of the 1070's, and typical of those built rapidly upon boroughs to assert the Norman presence. The castle was taken and destroyed by Henry II in 1173 (8a). Excavations in 1962 showed that the motte-top was of chalk rubble, and the north-east inner ditch had been recut and the bank heightened (9). Classified as an earthwork of exceptionally fine type (8). (8-12)
TL 874828. Castle Hill, scheduled. Norfolk 60.(13)
The motte is very steep-sided and stands 19.6m above the surrounding ground surface, 22m above the bottom of its encircling ditch. It is almost exactly circular with a basal diameter of 95m-100m. The top of the motte is occupied by a sub-rectangular depression some 20m square and upto 1.6m deep. Surrounding the motte is a steep-sided ditch which cuts into and sharpens up the face of the encircling inner rampart to the north, and also pulls away from its line leaving a berm behind the crest of the rampart close to a major breach in its line (see below) now followed by the modern footpath across the site. It is thus quite clear that the motte is a later feature inserted into an earlier (Iron Age) bivallate enclosure as the excavations (authorities 3 and 4) have suggested. This early enclosure has now been made the subject of a separate record (TL 88 SE 123). However, it is uncertain from the earthworks just how much of the surviving ramparts in this northern sector are prehistoric; they may have been remodelled to strengthen the defences of the castle around the motte.
It has previously been thought that the entire iron age enclosure was reused to serve as the bailey to the castle, whereas a combination of earthwork and documentary evidence indicates that the bailey occupied only a small part of the enclosure east of the motte. Immediately east of the motte the bailey ditch can be seen to spring off the motte ditch and breach the line of the inner rampart of the original Iron Age bivallate fort with the rampart realigned behind it to form the north-eastern wing wall of the bailey. This ditch then swings east and south-east seemingly at first reutilising and deepening the original iron age inner ditch with a heightened rampart behind. The earlier outer defensive line may here have been retained as part of the medieval defences. But towards Castle Lane both the inner (bailey) ditch and rampart pull in away from the course of the outer rampart suggesting that they here diverge from the line of the iron Age inner defences and that this part of the outer line may have played no part in the medieval castle defences. An eighteenth century plan of the earthworks around the castle (plate facing pp40 in auth 10) shows that this realigned inner rampart forming the bailey did not continue south to the river as has been claimed for the iron age enclosure (eg, auth 5), but curved to the south and west immediately east of Castle Lane and then back along the back of the properties at the east end of Old Market Street onto the west side of the motte to form a motte and bailey castle of conventional plan, with a bailey of only modest proportions. The bailey rampart east of Castle Lane was removed for manure in 1772 when it was observed to contain a masonry wall (14a). The motte and bailey castle so defined is centred at c TL8746 8281.
The earthworks are now mostly under mown grass and lie in an area of public parkland, although the sides of the motte are partly covered with scrub which was in process of being cleared at the time of survey. Also at time of survey a number of trees growing on the north-east slopes of the motte and on the surviving stretch of bailey rampart had recently blown down, leaving a series of deep holes and scars along the rampart crest in particular. Amorphous hollowing within the area of the bailey, now known as Military Parade, would seem to be post-medieval surface quarrying.
Earthworks surveyed at 1:1250 by RCHME for the OS's upgrade of the basic scale mapping of Thetford; plans, a level 3 descriptive text plus other associated archive material are held in the NMR archive. (14)
Scheduled. (15) |