Brent Knoll hillfort and associated field system


Heritage Category:
Scheduled Monument
List Entry Number:
Date first listed:
Date of most recent amendment:


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The building or site itself may lie within the boundary of more than one authority.

Sedgemoor (District Authority)
Brent Knoll
Sedgemoor (District Authority)
East Brent
National Grid Reference:
ST 34124 51021

Reasons for Designation

Large univallate hillforts are defined as fortified enclosures of varying shape, ranging in size between 1ha and 10ha, located on hilltops and surrounded by a single boundary comprising earthworks of massive proportions. They date to the Iron Age period, most having been constructed and used between the fourth century BC and the first century AD, although evidence for earlier use is present at most sites. The size of the earthworks reflects the ability of certain social groups to mobilise the labour necessary for works on such a monumental scale, and their function may have had as much to do with display as defence. Large univallate hillforts are also seen as centres of redistribution, both for subsistence products and items produced by craftsmen. The ramparts are of massive proportions except in locations where steepness of slope precludes easy access. They can vary between 6m and 20m wide and may survive to a height of 6m. The ditches can measure between 6m and 13m wide and between 3m and 5m deep. Access to the interior is generally provided by one or two entrances which often take the form of long passages formed by inturned ramparts and originally closed by a gate located towards the inner end of the passageway. The entrance may be flanked by guardrooms and/or accompanied by outworks. Internal features included timber or stone round houses; large storage pits and hearths; scattered postholes, stakeholes and gullies; and square or rectangular buildings supported by four to six posts, often represented by postholes, and interpreted as raised granaries. Large univallate hillforts are rare with between 50 and 100 examples recorded nationally. Most are located within southern England where they occur on the chalklands of Wessex, Sussex and Kent. The western edge of the distribution is marked by scattered examples in north Somerset and east Devon, while further examples occur in central and western England and outliers further north. Within this distribution considerable regional variation is apparent, both in their size, rampart structure and the presence or absence of individual components. In view of the rarity of large univallate hillforts and their importance in understanding the organisation and regional structure of Iron Age society, all examples with surviving archaeological remains are believed to be of national importance.

Brent Knoll fort is a good example of a large univallate hillfort, with a complete circuit of defences, an entranceway flanked by guardrooms, and a hollow way leading to it. Although much of the interior has subsequently been quarried, areas of undisturbed ground remain, and the discovery of Roman building foundations in the 19th century demonstrates that archaeological deposits survive. Snail shells are present in exposed soils, and this, together with other finds, demonstrates a high potential for environmental, dating and the recovery of occupation evidence. Strip lynchets to the north may overlie extra-mural features, or may themselves be outworks or contemporary fields. The site has been linked with the King Arthur legends. The area was border territory in the unsettled post-Roman period, and a fort in this strategic location may provide evidence for dates of Saxon penetration. Although Iron Age in origin, late Roman or early Dark Age reoccupation of hillforts is known from a number of sites in the area.


The monument includes a large univallate hillfort and associated field system on the top of Brent Knoll, an island in the surrounding levels rising to 139m at this point and overlooking a large area towards the Bristol Channel and inland. A low rampart c.1m high, with internal quarry ditches, encloses the 1.6ha flat top of the hill. The external face of this rampart falls steeply by c.2m to a step c.2.75m wide, beyond which the ground drops again c.2m-5m to a wider outer terrace c.4m-6m wide which may have originally been a ditch with counterscarp bank. Below this the ground falls away to the natural contour. The absence on the north eastern side of the outer terrace may suggest that this part of the site was left unfinished. The ramparts are constructed of stone or rubble, probably quarried from the interior. Eroded patches of the slope between the two terraces show a rough stone facing and in one place a line of cut stones. The entrance to the fort is on the east, where a hollow way, reused as a later quarry track, runs between slightly inturned ramparts. On the outer side the ramparts drop to form flanking platforms, thought to be guard houses. The southern of these is D-shaped, 12m by 8m; the northern is crescent shaped, formed of two D-shaped hollows 11m by 8m. Both may have been affected by or even created by later quarrying; however they do seem likely to be original. In a similar location on the lower terrace to the south of the entrance is a feature of comparable shape and size, perhaps representing a later extension of the gateway. The present track into the fort probably dates from the later quarrying of the interior and leads around the slope to form a wide hollow way curving across the field below. Just outside the fort entrance this appears to overlie an earlier narrow hollow way which can be seen running in a straight line down from the fort, crossed again by the later track at the bottom of the field. This earlier feature may represent the original approach to the fort. Towards the north end of the fort a narrow gap in the rampart, inturned on one side, may be an original feature. On the northern tip of the fort the step below the rampart drops to form a small platform, 7m by 5m. The lower terrace protrudes to form two bastions, and a large lynchet immediately below is possibly an additional rampart. These features may have guarded the north approach to the fort; the gap mentioned above perhaps provided access to them. A 35m stretch of the inner rampart on the west side is tumbled or levelled. A limestone quarry, probably medieval, has affected part of the interior to a depth of up to 1.5m. Quarrying seems to have begun near the entrance and spread out into the interior. Banks and mounds present may have been formed or heightened by quarry spoil. Despite this, areas of the original ground surface exist in the north and south west of the interior. Quarry pits inside the rampart along the west and north east are also considered to be original. Partial excavation of the interior in the early 19th century revealed a Roman building, probably in the north west of the fort. Across the spine of the hill immediately to the north of the fort are a series of single and double lynchets. These appear to be part of a strip-field system, probably medieval, traces of which can be seen around the entire hill, most notably on the south. The lower terrace of the fort, together with the two higher lynchets, has been used for military slit-trenching by the Home Guard in World War II. The site is considered to be Iron Age in origin, although the visible ramparts may be Roman. The outer terrace, if not original, may be a Dark Age re-fortification, seemingly incomplete. Legends associate the Knoll with King Arthur, and the fort has been claimed as the site of Mons Badonicus. Finds from the excavation include Iron Age pottery, Roman pottery and coins, Roman building material, charcoal and animal bones. Roman finds and settlement are common around the Knoll and nearby. Excluded from the scheduling are the Jubilee Stone and the flag mast, although the ground beneath these features is included.

MAP EXTRACT The site of the monument is shown on the attached map extract.


The contents of this record have been generated from a legacy data system.

Legacy System number:
Legacy System:


Books and journals
Burrow, I (.), Hillfort and Hilltop Settlement in Somerset, (1981), 70-300
Thackray, D, Archaeology in the National Trust: Somerset: Brent Knoll, (1980)
Thackray, D, Archaeology in the National Trust: Somerset: Brent Knoll, (1980)
Thackray, D, Archaeology in the National Trust: Somerset: Brent Knoll, (1980)
Dobson, D P, 'Antiquity' in Mount Badon Again, , Vol. 22, (1948), 43-45
HSL UK 71 216 RUN 33 1502 and RUN 35 1600, (1971)
HSL UK 71 216 RUN 35 1600 and RUN 33 1502, (1971)


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

End of official listing

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