Atlas of Hillforts of Britain and Ireland

SC1365: Dumbarton Castle  

(Dumbarton Rock; Dumbarton Military Hospital)

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HER:  The West of Scotland Archaeology Service 7926

NMR:  NS 47 SW 5 (43376)

SM:  90107

NGR:  NS 3998 7448

X:  239988  Y:  674485  (EPSG:27700)

Boundary:  

Summary

The presence of a major early medieval fortification, the seat of the kings of Strathclyde, which is implied by historical documentation spanning the period from the mid 5th to late 9th century, was confirmed in 1974-5 by the excavations directed by Leslie Alcock (Alcock and Alcock 1990). The rock rises abruptly from the N shore of the River Clyde into two summits at a height of some 74m OD, and is ideally suited to defence by virtue of the crags all around its compass. Having decided that the narrow pinnacle of the western summit of Dumbarton Rock was not in itself a suitable location for a nuclear fort, the excavation strategy tested the hypothesis that there had been a defended citadel on the summit of the eastern summit. Four trenches were excavated over visible scarps and terraces, and though one on the S yielded sherds of E Ware, amphorae and fragments of imported glass of early medieval date, and indeed other Roman sherds, no evidence of any early defences were located. In a fifth trench, however, lower down the eastern flank of the rock, outside the wall of the medieval castle, the bedding trench of a timber revetment, pieces of vitrified stone and evidence of burning were located, which were interpreted as the remains of a rampart with an external timber face and beams running back through an earth and stone core (Alcock and Alcock 1990, 108-13); three radiocarbon dates from the burnt timbers returned dates in the period from the 6th to the 9th century AD. While the presence of an early medieval fortification is thus confirmed, its character and extent are far from clear, and though there is no evidence of a prehistoric occupation it is unlikely that such a spectacular location was not utilised at an earlier date.

Status

Citizen Science:  ✗  

Reliability of Data:  Confirmed

Reliability of Interpretation:  Confirmed

Location

X:  -507984  Y:  7545836  (EPSG: 3857)

Longitude:  -4.563298  Latitude:  55.936756  (EPSG:4326)

Country:  Scotland

Current County or Unitary Authority:  West Dunbartonshire

Historic County:   Dunbartonshire

Current Parish/Community/Council/Townland:  Dumbarton

Condition

Extant:  
Cropmark:  
Likely Destroyed:  

Land Use

Woodland:  
Commercial Forestry Plantation:  
Parkland:  
Pasture (Grazing):  
Arable:  
Scrub/Bracken:  
Bare Outcrop:  
Heather/Moorland:  
Heath:  
Built-up:  
Coastal Grassland:  
Other:  

Landscape

Hillfort Type

Twin summits at 69m and 74m OD

Contour Fort:  
Partial Contour Fort:  
Promontory Fort:  
Hillslope Fort:  
Level Terrain Fort:  
Marsh Fort:  
Multiple Enclosure Fort:  

Topographic Position

Hilltop:  
Coastal Promontory:  
Inland Promontory:  
Valley Bottom:  
Knoll/Hillock/Outcrop:  
Ridge:  
Cliff/Plateau-edge/Scarp:  
Hillslope:  
Lowland:  
Spur:  

Dominant Topographic Feature:  Dumbarton Rock is a commanding and imposing feature of the inner Clyde estuary

Aspect

North:  
Northeast:  
East:  
Southeast:  
South:  
Southwest:  
West:  
Northwest:  
Level:  

Elevation

Altitude:  74.0m

Boundary

Boundary Type:  

Second HER:  

Second Current County or Unitary Authority:  

Second Historic County:  

Second Current Parish/Community/Council/Townland:  

Dating Evidence

While the dating of the rampart rests on three radiocarbon dates in the period from the 6th to the 9th century AD, the assemblage of fragments from imported pottery and glass vessels leaves no doubt about the early medieval occupation. It is likely, however, to have had a prehistoric predecessor.

Reliability:  A - High

Pre 1200BC:  
1200BC - 800BC:  
1200BC - 800BC:  
400BC - AD50:  
AD50 - AD400:  
AD400 - AD 800:  
Post AD800:  
Unknown:  

Pre Hillfort Activity:  ✗  

Post Hillfort Activity:  ✓  Medieval castle and post-medieval battery and garrison

Artefactual:  E ware, amphorae, glass
C14:  Three radiocarbon dates
Other:  Literary identification

Investigations

While David Christison hints at the presence of an unrealised fortification on Dumbarton Rock in a comparison with Dunadd in Argyll (Christison 1904, 226), it was Robert Stevenson who included it into his paper defining the character of nuclear forts (Stevenson 1949, 196). The first recorded archaeological fieldwork, however, is by the RCAHMS Survey of Marginal Lands, which, like Alcock, concluded that the eastern summit was the more likely site, observing 'One or two terraces on the W side of the lower peak have an artificial appearance and could be the quarried seatings for ramparts, but there is no trace of walling either here or elsewhere on the hill'. In addition to the excavations by Lelsie Alcock in 1974-5, there have been at least twelve watching briefs carried out within the castle, but none has revealed any early medieval deposits. The site was Scheduled in 1994.

Other (1955):  Description by RCAHMS Survey of Marginal Lands
Excavation (1974):  (Alcock and Alcock 1990)
Excavation (1975):  (Alcock and Alcock 1990)
Other (1994):  Scheduled

Interior Features

Taken up by medieval and later features of the castle

Water Source

None:  
Spring:  
Stream:  
Pool:  
Flush:  
Well:  
Other:  

Surface

No Known Features:  
Round Stone Structures:  
Rectangular Stone Structures:  
Curvilinear Platforms:  
Other Roundhouse Evidence:  
Pits:  
Quarry Hollows:  
Other:  

Excavation

No Known Excavation:  
Pits:  
Postholes:  
Roundhouses:  
Rectangular Structures:  
Roads/Tracks:  
Quarry Hollows:  
Other:  
Nothing Found:  

Geophysics

No Known Geophysics:  
Pits:  
Roundhouses:  
Rectangular Structures:  
Roads/Tracks:  
Quarry Hollows:  
Other:  
Nothing Found:  

Finds

Finds include sherds of E-ware and amphorae, glass fragments from continental vessels, crucible fragments and two knives; Roman sherds were also recovered (Alcock et al 1992).

No Known Finds:  
Pottery:  
Metal:  
Metalworking:  
Human Bones:  
Animal Bones:  
Lithics:  
Environmental:  
Other:  

Aerial

NO APPARENT FEATURES

APs Not Checked:  
None:  
Roundhouses:  
Rectangular Structures:  
Pits:  
Postholes:  
Roads/Tracks:  
Other:  

Entrances

None known

Total Number of Breaks Through Ramparts:  0:  Precise circuit is unknown

Number of Possible Original Entrances:  0:  No entrances recorded

Guard Chambers:  

Chevaux de Frise:  ✗  

Enclosing Works

Single rampart found in excavation, but its extent is unknown

Enclosed Area 1:  
Enclosed Area 2:  
Enclosed Area 3:  
Enclosed Area 4:  
Total Enclosed Area:  

Total Footprint Area:  

Multi-period Enclosure System:  ✗  Area unknown

Ramparts Form a Continuous Circuit:  ✗  Rampart only recognised in a single trench

Number of Ramparts:  1

Number of Ramparts NE Quadrant:  1
Number of Ramparts SE Quadrant:  
Number of Ramparts SW Quadrant:  
Number of Ramparts NW Quadrant:  

Current Morphology

Partial Univallate:  
Univallate:  
Partial Bivallate:  
Bivallate:
Partial Multivallate:  
Multivallate:  
Unknown:  

Multi-period Morphology

Partial Univallate:  
Univallate:  
Partial Bivallate:  
Bivallate:  
Partial Multivallate:  
Multivallate:  

Surface Evidence

None:  
Earthen Bank:  
Stone Wall:  
Rubble:  
Wall-walk:  
Evidence of Timber:  
Vitrification:  
Other Burning:  
Palisade:  
Counter Scarp Bank:  
Berm:  
Unfinished:  
Other:  

Excavated Evidence

Timber-faced with a rubble core

None:  
Earthen Bank:  
Stone Wall:  
Murus Duplex:  
Timber-framed:  
Timber-laced:  
Vitrification:  
Other Burning:  
Palisade:  
Counter Scarp Bank:  
Berm:  
Unfinished:  
No Known Excavation:  
Other:  

Gang Working

Gang Working:  ✗ 

Ditches

Ditches:  

Number of Ditches:  

Annex

Annex:  ✗  

References

Alcock, L (1976) 'A multi-disciplinary chronology for Alt Clut, Castle Rock, Dumbarton'. Proc Soc Antiq Scot 107 (1975-6), 103-13

Alcock and Alcock, L and E A (1990) 'Reconnaissance excavations on Early Historic fortifications and other royal sites in Scotland, 1974-84: 4, excavations at Alt Clut, Clyde Rock, Strathclyde, 1974-75'. Proc Soc Antiq Scot 120 (1990), 95-149; fiche 2

Alcock, L, Bateson, J D and Webster, P V (1992) 'Excavations at Alt Clut, 1974-5: catalogue of coins, metal objects and Romano-British pottery', Proc Soc Antiq Scot 22 (1992), 289-93.

Feachem, R W (1963) Guide to prehistoric Scotland. Batsford, London (p 118)

Terms of Use

The online version of the Atlas of Hillforts of Britain and Ireland should be cited as:

Lock, G. and Ralston, I. 2017.  Atlas of Hillforts of Britain and Ireland. [ONLINE] Available at: https://hillforts.arch.ox.ac.uk.

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