NHER 52201 (Cropmark and Earthwork record) - Possible kite-shaped enclosure around Venta Icenorum

Some of these cropmarks were previously recorded under NHER 9836.

March 2009. Norfolk NMP.
The site of a possible triple-ditched kite-shaped enclosure surrounding the Roman town of Venta Icenorum (NHER 9786) has been suggested from aerial photographic evidence (S1-S5). The site is centred on TG 2312 0352. Parts of this triple-ditch enclosure were previously recorded under NHER 9836. The aerial photographic evidence has long attested to the presence of a triple ditch system to the south and east of the town (NHER 52202). These features have commonly been interpreted as indicating the presence of an early Roman fort or military base, associated with the pacification of the local Iceni inhabitants around and after the time of the Boudican revolt (S6-S7). Prior to NMP the presence of the triple ditches had not been recognised to the north and west of the town.
Consultation of a variety of historic vertical and oblique aerial photographs has identified these features to the northwest (NHER 52203) and northeast (NHER 52204) of the town (S2, S4-S5). It had previously been supposed that the northern line of the triple ditches followed that of the northern wall of the town, however the new aerial photograph evidence would suggest that this is not the case. Nearly all sections of these four separate triple ditch defences measure 17-18m across in total, with ditches generally between 2-4m across. See NHER 52202-4 for details of each section. Given their proximity, alignments and this similarity in size and positioning it seems reasonable to suggest that they are part of the same defensive scheme and potentially even the same defensive enclosure. It could be assumed that if the triple ditches continued to the west of the town, and they may not have needed to due to the proximity of the river along the western side of the town, they may have followed the alignment of the northwestern section of wall. Further aerial photograph or geophysical survey would be required to ascertain the line of the defences in this area. Joining all of these separate triple ditch segments up it is possible to suggest a kite-shaped arrangement of ditches. This kite-shaped enclosure, centred on TG 2312 0352, measures approximately 900m by 680m along its longest axis. The northeastern end of this hypothetical polygonal enclosure is bisected by the route of the Roman road leading northeast out of the town, the route of the existing Stoke Road (see below for discussion of this road).
The triple ditches have most commonly been interpreted as relating to a defended Roman military base that pre-dates the town, associated with the pacification of the local Iceni inhabitants around and after the time of the Boudican revolt (S6-S7). It has been argued by Vivien Swan that the kilns excavated are indicative of pottery produced to supply a military establishment of mid to late first century AD date late (S8). This combined with the presence of military equipment on the area (S6-S7) quite convincingly suggests that presence of a fort on or around the site of the later town. It was suggested by Wacher (S6) that this may lie to the north-east of the town, where there is a cluster of early Roman material, within the grounds of Caistor Hall, an area with landuse not conducive to recognition through aerial photographic methods. A small fort within the SW area of the town, now entirely covered and obscured by town deposits and layers has also been suggested by Swan (S8). However the possible extension of the triple ditches to the north identified on the aerial photographs (NHER 52203-4) to potentially create a large kite-shaped enclosure would be an unusually large fort, even for a legionary base. The dimensions of up to 900m by 680m make it almost twice the size of the legionary fort that preceded Roman York. It is also worth noting that Wacher thought it unlikely that a full-sized legionary fort would ever have been built at Caistor (S6). Excavations in 1997 across a section of the southern ditches, as well as revealing a minor fourth ditch, indicated that at least one of the ditches was deliberately backfilled in the later 2nd century (S9), which could suggest that if the ditches were originally constructed as part of an early fort, they must have stayed in use for a considerable period afterwards. The possible polygonal or kite-shaped plan would probably also more indicative of a Roman civil defence than a military fort, with the polygonal town defences at Chesterton and Ilchester, providing comparable plans.
On the aerial photograph evidenced alone it is obviously extremely hard to be definite about stratigraphical relationships, however the aerial photographs tend to suggest that the triple ditch system post-dates the road network to the east of the town (see NHER 52230 for detailed discussion of these cropmarks), and this is also the view also put forward by Wacher (S6). This implied relationship indicates that the triple ditches do not relate to an earlier and short-lived military site, unless they were re-cut during a later phase of development of the town. The sequence identified at Pakenham in Suffolk may provide some interesting potential parallels. The site consisted of a triple-ditched post-Boudiccan fort that was short-lived and lacked permanent buildings. Of the perimeter ditches the innermost was rapidly backfilled with almost archaeologically sterile material, probably related to the levelling of the accompanying rampart. The middle and outer ditches remained visible depressions well into the 2nd and 3rd centuries, and in places were re-used and backfilled as late as the 4th century (S10). A similar sequence of re-establishing of earlier boundaries could account for the fact that some of the roads at Caistor appear to ignore the ditches, whilst others are cut by them. Obviously only more excavation of these ditches would resolve this issue of data and sequence. The fact that the triple ditches appeared to post-date some of the roads to the east of the town led Wacher (S6) to suggest that the triple ditches could relate to civil town defences. He felt that these could be comparable to those constructed around other Roman small towns and civitas capitals in the second century and later, but felt that that the construction of a triple ditch was atypical for civic defences. However evidence has since arisen to suggest that these were not so atypical. Triple ditch systems surrounding the Roman towns at Whilton Lodge, Great Casterton, Chelmsford and Irchester have all been suggested, with excavations revealing sequences of ditch recutting and modification from the late 2nd century to the 4th century AD (S11).
The long axis of the possible kite-shape appears to be bisected by the diagonal Roman Stoke road leading from the centre of the town to the northeast. It has been assumed that this road is quite early in the sequence of the town grid and potentially pre-dating it (S6-S7). The arrangement of this diagonal road and the street grid is reminiscent of the diagonal alignment of the Watling Street as it enters Verulamium, St Albans (S6). It was also thought that this road also led to a pre-town fort, although the location or even the presence of this is uncertain. At St Albans the construction of the Fosse defensive system in the later second century has many similarities in the shape and arrangement of the Caistor enclosure, where Watling Street bisects a polygonal face of a large polygonal enclosure that circuits the town. This would suggest that even if the diagonal road at Caistor is the earliest component of the street grid, then this does not need to also indicate that the kite-shaped enclosure, that is potentially aligned along it – as opposed to the main street grid, is also an early component.
S. Horlock (NMP), 29 March 2009.