The steep-sided earthwork, 60m in diameter at the base, survives to 10m above the present ground surface, and is surrounded by a dry ditch c.3.5m deep and between 10m and 12m wide. Very little evidence of the bailey appeared to have survived. No evidence of a stockade or major fortification ditches was found, although the presence of two parallel ditches indicate a palisade. The Norman church stands immediately south of the mound and may originally have stood within the bailey. The work is on high ground which drops sharply towards a stream to the W; on the slope is a nearly rectangular area scarped on three sides, with an oblong depression near the W side. This is probably the site of a terraced garden to the hall. Plan and section of motte in RCHME. J.H. Round said 'I have been disposed to think that Mount Bures may have been the castle of the Sackvilles, raised perhaps in the anarchy under Stephen (1135-1154) or possibly under Henry I (1100-1135)' However the early C12 date of the church and the scale in proportions of the motte suggest that it is an early example of its type. (Derived from Unlocking Essex's Past)
The absence of cut features on the motte summit which could have held the foundations of large timber buildings such as a defensive tower or lord's residence suggests that if there was a timber structure on the top of the motte, this must have been small with little or no sub-surface foundations. Just 11 sherds of pottery were found in the 40 square metres excavated on the motte top: four of these were modern ironstone china of 19th or 20th century date (possibly associated with the previous unrecorded excavations on the site) while a further sherd dated to the Roman period and was residual in later layers. The other six sherds were medieval in date, comprising five sherds of Early Medieval Sandy Coarsewares (12th 14th century) and one of Hedingham Fine Ware (late 12th 14th century). The scarcity of archaeological finds indicates that the motte was not permanently occupied or manned. All this, combined with its unusual height (10m) and its prominent location providing superb views for miles in all directions, suggest it was used as a lookout post in the medieval period, rather than as a residence, military storehouse, prison or defensive retreat. The medieval motte may have been built by enlarging a pre-existing burial mound, as Bronze Age (1500-800 BC) pottery and struck and burnt flint was found in excavations nearby.
The 2011 excavations, along with surface examination of the sides of the mound, indicate that the medieval motte was built as a series of tiered concentric circular layers which were reduced in diameter as the motte increased in height. These layers were mostly made up of the sandy gravel sub-soil naturally occurring in the immediate area, which was methodically removed from around the base of the motte to create the deep ditch which surrounds the mound. The 2011 excavations (including a sondage into the backfill of a very deep earlier unrecorded excavation) showed that the loose sandy fabric of the mound was stabilised by building a retaining ring of clay around the mound perimeter, and by carefully levelling every load of spoil before the next was added.
It has been suggested that a bailey (an enclosed, defended yard containing residential and ancillary buildings associated with the motte) may have lain in the area now occupied by the churchyard. There is no historical or archaeological evidence for this, but the suggestion is not unreasonable and is made on the grounds that (a) most medieval mottes are associated with at least one bailey (b) the churchyard is the most likely place as it is on level ground and includes the present parish church, whose graveyard may have concealed the earthworks of a bailey and (c) there is no evidence whatsoever for any bailey elsewhere around the motte, where traces of such a feature would be expected to be visible in the un-built upon land. Although there is today a scarp around the edge of the churchyard which might represent the denuded remains of a bailey bank, this may equally be due to the raising of the ground surface in the burial ground. The 2011 excavations did not produce any definitive evidence for a bailey in this area, such as a ditch or bank, but the presence of undoubted domestic occupation contemporary with the motte immediately adjacent to the church does suggest this is the location of a seigniorial manor/church complex linked to the motte. This thus gives some support to the suggestion that there may have been a bailey here. Whether or not this actually did exist, however, remains unproven.
In the twelfth century, probably during the Anarchy of Stephen and Matilda when a lack of effective royal control of warring factions threatened the security of all, a substantial motte was built adjacent to the manorial complex (perhaps enlarging the pre-existing remains of a prehistoric burial mound), Defences built at this time may, just possibly, also have included a bailey enclosing within it the manorial site, the church and any other contemporary settlement. With or without a bailey, this very prominent motte would have looked highly defensible while also providing a good strategic lookout post. It was not intensively used, with no large keep or watch tower on top of it; although a small, timber-framed look-out structure may conceivably have surmounted the mound. It did not continue in use after the 12th century, although must have remained a useful vantage point. (Lewis, 2011)