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Dumbarton Castle

Castle (Medieval), Fort (Early Medieval)(Possible), Hospital (First World War)(Possible)

Site Name Dumbarton Castle

Classification Castle (Medieval), Fort (Early Medieval)(Possible), Hospital (First World War)(Possible)

Alternative Name(s) Dumbarton Rock; Dumbarton Military Hospital

Canmore ID 43376

Site Number NS47SW 5

NGR NS 39988 74485

NGR Description Centred on NS 39988 74485

Datum OSGB36 - NGR

C14 Radiocarbon Dating


Ordnance Survey licence number 100057073. All rights reserved.
© Copyright and database right 2017.

Digital Images

Administrative Areas

  • Council West Dunbartonshire
  • Parish Dumbarton
  • Former Region Strathclyde
  • Former District Dumbarton
  • Former County Dunbartonshire

Archaeology Notes

NS47SW 5.00 centred 39988 74485

(NS 4000 7446) Dumbarton Castle (NAT)

OS 6" map (1922)

NS47SW 5.01 NS c. 3998 7441 Chapel

NS47SW 5.02 NS 40010 74407 Governor's House

Dumbarton Castle. For historical and architectural description see Guide.

I MacIvor 1958

Apart from the fragmentary remains of the White and Wallace Towers, and the Portcullis Arch, all as described by MacIvor, the buildings and walls which now form the Castle, date from the 18th and 19th centuries.

Visited by OS (JLD) 29 November 1960

The principal objective of the work was to seek archaeological evidence which might be correlated with the well-known documentary evidence for Dumbarton (which some identify with Alcluith) as an important British stronghold in the Early Historic period. In particular, traces of possible early defences had been detected on the Beak, the larger of the two hills which comprise Castle Rock; and these traces were tested by excavation.

Four trenches were excavated on the Beak and the findings in each are summarized here.

Trench A examined a sharp slope on the W side of the hill, above an apparently rock-hewn passage-way. The discovery of a turf-stack containing a sherd of Antonine Samian gave high promise of an early defence; but the rubble foundation of the turf bank overlay green-glazed pottery. It seems likely that the structure was the flag-pole mound seen in Slezer's drawing of about 1693.

Trench B examined the flat top of the hill. The level ground was found to be a make-up of ash and cinders. This may perhaps be dated to the mid 16th century by two pieces of Charles I, but was deeply disturbed by rubbish pits of the 1939-45 war.

Trench C examined a bank on the E side of the hill, and showed that it was later than a layer of mason's chips from the mid 18th century magazine.

Trench D was sited on a quarried ledge on the Clyde-ward side of the hill. Modern debris was less abundant here, and there were tenuous traces of drystone and timber buildings. These could not be fully explored in the time available, and Trench D demands further exploration. Finds included two silver pennies of Edward I - Edward II, and a strap-handle from an 'E-ware' pitcher of Dunadd type.

it is clear that there are no visible traces of defences earlier than those of the medieval castle. (this does not exclude the possible existence of buried traces). Moreover, the demonstration that all the areas of level ground on the E hill are recent creations implies that this hill was originally rugged and craggy as the W one.

L C Alcock 1974

A second season of excavation explored rock-cut terraces on each of the twin summits. The W terraces yielded principally recent pottery and appeared to have been garden plots using earlier stone quarries. The E terrace had carried some form of timber buildings, but contained material swept off thesummit. This ranged back from building debris of 1939-45, and included fragments of mail; iron tools and arrowheads; a dispersed hoard of Edward I and II; a few sherds of Saintonge ware and much green-glazed; fragments of probable Merovingian glass; post-Roman import wares of class Bi, Bii and E; and a very little Roman pottery.

Outside the medieval and later curtain, on the E spur of the Rock, traces were found of a timber-and rubble rampart which had been burnt and partly vitrified. It is doubtful whether this had formed a continuous enceinte; and the purpose of the defence-work as explored had probably been to control access to the Rock across a tidal isthmus. This work may have been destroyed in AD 780 (when Annals of Ulster record the burning of Dumbarton) or after a Hiberno-Norse siege in AD 871-2. Finds apparently from the destruction of the rampart included a Norse lead weight decorated with a glass bangle fragment of Lagore type, and an iron sword pommel with Irish parallels. The rampart itself probably formed part of bede's civitas Brettonim munitissima (HEi, 1).

L C Alcock 1975

NS 400 744 Recent excavations have shown that Castle Rock was fortified during the Early Historic Period and may be the Alduith described by Bede as a political centre of the Britons. Most of the remains now visible, however, are of 17th-and 18th-century date and very little survives even of the medieval castle that subsequently occupied the site.

December 1977

DES (1974), 32-3; Alcock 1975; DES (1975), 19-20;

Alcock 1976

Excavations were carried out in 1974-5 at Dumbarton Castle, anciently known as Alt Clut or Clyde Rock. They revealed a timber and rubble defence of Early Historic date overlooking the isthmus which links the rock to the mainland. Finds include the northernmost examples of imported Mediterranean amphorae of the 6th century AD, and fragments from at least six glass vessels of germanic manufacture.

L Alcock and E A Alcock 1991.

NS 400 745 A watching brief was maintained during the excavation by Historic Scotland staff of a power cable trench in an area immediately E of the Governor's House, latterly a garden. Masonry dating from the earlier Gatehouse (demolished in advance of the 18th century artillery fortification) was revealed running E-W close to the E wall of the Governor's House (NS47SW 5.02).

Sponsor: Historic Scotland.

G Ewart 1995.

NS 4000 7446 A watching brief was undertaken in October 2000 during minor excavations at the powder magazine at Dumbarton Castle (NMRS NS47SW 5). No significant discoveries were made.

A further watching brief was undertaken in March 2001 while contractors excavated a series of trial pits in and around the French prison. The purpose of the trial pits was to investigate the subsidence presently afflicting the W wall of the building. The pits were dug at various strategic points in order to determine the nature of the underlying deposits, as well as checking the strength of the foundations.

In total, the evidence from the pits regarding the stability of the French prison masonry revealed that the long E wall of the building is built directly on bedrock while the W frontage sits on and within a soft fairly wet sludgy silt. The result of this positioning is an inevitable settlement of the W side of the structure.

Trial trenching was undertaken in May 2001 in an attempt to recover the line of an 18th-century sentry path believed to have existed along the inside face of the N curtain wall, where it runs between the Wallace Tower and the Argyll Battery. Remains of unmortared paving were found only at the W end of the wall; elsewhere the stones seem to have been removed. Various 17th to 20th-century midden deposits were found accumulated against the inner face of the curtain wall, while the wall itself was seen to sit on top of a lower wall, potentially an earlier perimeter.

Sponsor: Historic Scotland

G Ewart and A Dunn 2001

NS 400 744 A small cable trench was excavated in February 2002 adjacent to the W wall of the steps leading from the Governor's House to the Guardhouse. A small stump of an earlier wall was found protruding from under the present wall on the garden terrace below the Guardhouse. This was possibly the remains of an earlier approach to the entrance to the upper castle, leading from the probable site of the medieval Hall, to the W of the Governor's House, thus adding weight to the theory of this being the original location of the Hall.

Archive to be deposited in the NMRS.

Sponsor: HS

G Ewart and J Franklin 2002

NS 400 744 Three small pits were excavated in February 2003 to erect a gate in the gap between the Governor¿s House and the parapet wall of the King George Battery. Levelling layers were found, including building debris from various periods of construction, possibly relating to the laying of the path or the building of the King George Battery.

Archive to be deposited in the NMRS.

Sponsor: HS

G Ewart, D Stewart 2003

NS 400 744 Archaeological monitoring was undertaken in March 2004 during the excavation of foundation pads for a

handrail by the flight of stairs near the Governor¿s House, with a light gravel path covering the areas at the top and bottom of the steps. There were no finds of archaeological significance.

The need to erect scaffolding over the Inner Gateway and drawbridge required monitoring of clearance of turf and topsoil over bedrock on the E side of the gate. Nothing of archaeological interest was revealed.

Archive to be deposited in the NMRS.

Sponsor: HS.

A Radley 2004

Watching brief NS 4005 7440 A watching brief was undertaken in October 2004 during the clearing and removal of vegetation and soil in an area near the portcullis on the E side of the main stairway through the castle complex (NS47SW 5.00). This area consisted of a purpose-built platform just S of the E side of the portcullis. The platform measured c 5 x 2m, with a roughly metalled or cobbled surface, and no clear structural function beyond the reinforcement of the

rock face.

The shallow excavations required for the creation of new bicycle racks on the bowling green immediately within the castle compound was monitored. Nothing of archaeological interest was revealed.

NS 3999 7448 A number of artefacts were found by a visitor, and the area where they were reported to have been discovered was examined: on the surface to the W of the staircase leading from the guardhouse to the portcullis arch. The finds include a copper-alloy coin, green-glazed pottery, a piece of black glass or black glazed pottery, clay pipe stems, a small quantity of animal bone, and a number of sherds of white glazed and patterned pottery. These finds

were unstratified and are of limited archaeological interest.

Archive to be deposited in NMRS.

Sponsor: HS.

C Shaw 2005

Evaluation; watching brief NS 4000 7440 A short programme of clearance and evaluation was undertaken in January 2005. The site consisted of the walled-off area below King George¿s Battery on the S side of Dumbarton Castle rock, an irregular-shaped courtyard containing two adjoined buildings. It was hoped that original occupation surfaces might be

revealed; in particular, the cobbled W half of the site was expected to exhibit the footprints of lost structures. Following this initial work, a watching brief was undertaken while contractors cut a number of drain and foundation trenches.

This area appears to have been a Victorian addition, set against the old sea wall of a Georgian gun battery. All structures and features seen during these works therefore date from the mid- and late 19th century to the late 20th century. The basic structure is mostly intact, comprising the new sea wall, the two store sheds and the general levelling deposits. An original gateway positioned halfway down the compound had been demolished, probably to improve access to the end of the site. The cobbling at the W end of the site seemed to respect the line of the gateway and consequently was probably in place while the gateway was in use.

NS 3996 7453 A small excavation was undertaken in July 2005 around the French Prison, which lies just S of the Duke of York¿s Battery. The aim was to examine the foundations to assess the nature of the underlying material and assist in establishing suitable areas for engineering work.

Previous archaeological work had been carried out on the N and W sides of the building (DES 2001, 98) in the form of

small trial trenches with similar criteria. This was expanded upon, exploring additional sections of the building in order to ascertain the relationship between the building and the underlying bedrock. Stone-lined drains and other features were exposed and recorded, which appeared to pre-date the French Prison.

Archive to be deposited in NMRS.

Sponsor: HS.

D Stewart 2005.

Architecture Notes

NS47SW 5.00 39988 74485


In the National Library of Scotland is a series of Military Maps and Drawings (many are coloured) of the Board of Ordnance, relating to the works executed in the 18th Century. Reference "MSS. 1645 - 1652".

In Volume or Case No.1647 are the following Drawings relating to the Castle of Dumbarton:- which is under the charge of the Commissioners of H.M.Works:-

No. Z.2/71.- "A Draught of Dumberton Castle", with Explanation, Anno 1708.

Scale 60 Feet to an Inch. There is also a copy.

Z.2/72.- "A Plan of the Castle of Dunbarton and the repairs requisite 1709".

Scale 35 Feet to an Inch. With Reference.

Z.2/73. "Dunbarton Anno 1719". Various Plans and Sections of the Buildings.

Scale 10 Feet to an Inch.

Z.2/74. "A Design for a Powder Magazine proposed to be built at Dumbarton Castle", 1748. Scale 5 Feet to an Inch. Signed by W. Skinner. There is also a Copy.

There are also in Volume or Case No. 1649:-

No. Z.3/49. "Plan of part of the North-end of Dunbarton Castle and proposed Situation for a Barrack &c with designs for same". Scale 24 Feet to an Inch. No date. Signed by H. Rudyard, Captn, Rl. Engineers.

Z.3/55. "Plan of the Castle of Dunbarton" with two views in monotone. There is a note appended to the effect that the Plan was "Handed over to Lieut. Monier Skinner, Rl.Engineers by his father in 1872". The Plan itself is not dated.

In the Edinburgh Evening Courant of August 17th, 1844, it was reported that "The Governorship of Dumberton Castle having been abolished upon the demise of General Lord Lynedoch, the Governor's Houseand premises fall into the Board of Ordnance; and the intention is there to establish a military prison for North Britain".

The National Library of Scotland, Edinburgh, contains, among the 'Uncatalogued MSS of General Hutton', and numbered 35 in Vol.11, a Sketch of a Gate in Dumbarton Castle, copied from a Drawing by Capr. Columbine, R.N.



Repair of the Castle of Dumbarton.

Letter (copy) from the Earl of Mar to James, Duke of Lennox.

He explains that lack of money delays repair.


GD 124/15/77


Field Visit (5 May 1955)

This site was included within the RCAHMS Marginal Land Survey (1950-1962), an unpublished rescue project. Site descriptions, organised by county, are available to view online - see the searchable PDF in 'Digital Items'. These vary from short notes, to lengthy and full descriptions. Contemporary plane-table surveys and inked drawings, where available, can be viewed online in most cases - see 'Digital Images'. The original typecripts, notebooks and drawings can also be viewed in the RCAHMS search room.

Information from RCAHMS (GFG) 19 July 2013.

Publication Account (1985)

The twin peaks of Dumbarton Rock (a volcanic plug similar in origin to Edinburgh and Stirling Castle Hills) rise dramatically from the north shore of the Clyde at its confluence with the River Leven to form a site of great natural strength, which is reputed to have the longest recorded history of any fortification in Britain. From at least the 5th century AD it served as the principal stronghold of the Britons of Strathclyde, thereafter it was a royal castle, and during the postmedieval period the castle was used as an artillery fortress guarding the approaches to Glasgow.

Little now survives of the early historic fortifications or of the urbs (town) mentioned by Bede, but excavations carried out by Professor Alcock in 1974-5 revealed the remains of a rampart on the east peak, as well as finds of imported Mediterranean pottery and Merovingian glass. These, and the radiocarbon dates obtained from the rampart, tie in with the early documentary references to the site in the period AD 400-1000, when it was known to the Britons as Alcluith (Clyde Rock) and to the Irish annalists as Dun Breatann (Fort of the Britons). It is clear from the early references that the site was frequently attacked, and it owed its strategic significance to its proximity to the ford across the Clyde at Dumbuck (2km to the east), which, until the channel was artificially deepened in recent times, was the lowest crossing point of the river.

Apart from sections of the Curtain Wall and the 14th century Portcullis Arch, which guards the way up through the cleft between the two peaks, the medieval castle has been all but obliterated by the post-medieval fortifications. The advent of artillery necessitated a major reorganisation of the defences, and during the 16th and 17th centuries a series of batteries was built to cover the river and the approaches to the castle, Following the troubles of 1715 the defences were further improved with the addition of King George's Battery and the construction of the Governor's House (1735) at its rear. Minor alterations were made during the Napoleonic Wars, and the castle was last refortified during World War II when it was equipped with an anti-aircraft battely.

Information from ‘Exploring Scotland’s Heritage: The Clyde Estuary and Central Region’, (1985).

Excavation (16 December 1996 - 20 December 1996)

NS 4000 7446 A watching brief and small excavation were conducted at Dumbarton Castle by Kirkdale Archaeology in December 1996. The works involved the clearance of 300mm of floor deposits in the 18th-century powder magazine, in advance of the installation of a new floor and the opening of the magazine exhibition to the public. In addition, a small trench was excavated to the W of the 18th-century Governor's House, in advance of the installation of a moveable gate-post.

Various backfilling and levelling deposits were found in the trench; a lead pipe, some 60-80mm in diameter, was found at a depth of 450mm. The remains of a capped drain were also revealed. This feature ran parallel to, and may have formerly served the Governor's House. No datable finds were revealed. The drain comprised well-mortared dolerite blocks on the E side and a single red sandstone slab on the W, with an irregular flattened dolerite slab collapsing into the channel so defined. The survival of the drain indicates that such features may survive beneath 1735 levelling material. It is of particular interest that the levelling medium may even overlie the remains of the medieval gate-house and nether bailey.

Clearance work was undertaken in the powder magazine, situated at the second highest point of the rock, known as 'The Beak', and measured 4.4 x 5.2m internally. The building was erected in 1748, replacing an earlier magazine on the site. The in situ floor deposit comprised random brick rubble and mortar-rich sand. The bricks were relatively modern, being frogged and uniformly sized. The original sprung timber floor would have lain some 200mm below the present surface, resting on slight ledges protruding from the bases of the interior long walls, which were founded directly on the bedrock. The brick rubble deposit represents a period post-dating the use of the building to store explosives, as it blocked the vents in the long walls necessary to maintain a damp-free environment internally. Finds include occasional iron nails, and three larger iron bars. None of the finds were removed from the site

Sponsor: Historic Scotland

G Ewart and A Dunn 1997

Publication Account (1999)

There are only two structures in Dumbarton older than Glencairn House. The first, Dumbarton Castle figure 24, reflects the town's traditional role-as a military stronghold. The castle stands apart from the centre of the town, on two volcanic peaks, at the mouth of the River Leven figure 2. Dumbarton Rock, it has been claimed, is the oldest known, continuously recorded, stronghold in Great Britain with occupation from at least AD 460. The oldest structure now standing on the rock, the portcullis arch, dates from the fourteenth century figure 17. A sixteenth-century guardhouse figure 17 and the slightly later Wallace Tower figure 25 (rebuilt in 161 7 on a medieval site and covered, in the late eighteenth century, by the Duke ef York's Battery), represent periods of building work considerably earlier than the majority of structures still standing on the rock.

Unfortunately, little survives even of the medieval castle, and much of what is visible today is of the seventeenth-and eighteenth-century fortifications. Almost continuous use of the Rock over 1,500 years has meant that the most suitable areas for occupation have been built over time and time again. Fortifications, by their very nature, are massively constructed, with deep foundations, and would probably destroy all traces of earlier activity. Nevertheless, the excavations of 197 4--5 and the discovery of two cross-slabs clearly demonstrate the archaeological potential of this site. The castle is a Scheduled Ancient Monument and is in the care of Historic Scotland.

Information from ‘Historic Dumbarton: The Archaeological Implications of Development’ (1999).

Watching Brief (November 2006 - March 2007)

NS 3996 7453 A small excavation and assessment took place over four days at Dumbarton Castle during November 2006. The French Prison had been deteriorating badly and this was particularly evident in the badly cracked W wall of the E ground floor room and E wall of the small room at the base of the stairs.

To investigate these problems two trenches were opened - one to investigate the wall foundations in the E room, and the other to examine the base of the stairs. The excavations revealed an earlier floor level, probably dating to the first half of the 20th century, and also deposits associated with levelling for, and the construction of, the French Prison (1795). The N part of the trench in the E room was excavated as far as bedrock and it was

discovered that only the N wall as built directly onto bedrock, with the other walls built onto imported levelling material. This appeared to be the cause of the slumping and subsequent cracking of the walls.

These trenches showed evidence of the installation of a timber floor and confirmed the sloping or terraced nature of the bedrock, dropping steeply from N to S. Levelling material up to 1.5m deep was imported towards the S of the trench to form a platform for the late 18th-century building campaign.

A further visit comprising excavation and assessment took place outside the French Prison during February and March 2007. Trenches were excavated along the length of the S wall and W wall. The former was dug to a depth of 0.8m and revealed evidence of medieval industrial activity. The other trench was dug to a depth of 0.7m and revealed traces of a toilet block apparently demolished before 1928, on the basis of photographic evidence.

Archive to be deposited with RCAHMS.

Funder: Historic Scotland.

OASIS ID: kirkdale1-249653

Watching Brief (3 February 2009)

NS 3996 7452 A watching brief was maintained on 3 February 2009 during the excavation of 11 small holes around the flight of steps down to the cistern to the SW of the French Prison, to allow the installation of a new handrail. Masonry seen in the holes probably represented an access structure pre-dating the current modern steps.

Archive: RCAHMS (intended)

Funder: Historic Scotland

Gordon Ewart – Kirkdale Archaeology

OASIS ID: kirkdale1-249672

Watching Brief (10 June 2010)

NS 3998 7448 (centred on)

A watching brief was maintained on 10 June 2010 during the excavation of three trenches in advance of the installation of wooden posts associated with a new interpretive trail. There were no finds or features of archaeological significance.

Archive: RCAHMS (intended)

Funder: Historic Scotland

P Fox 2010

OASIS ID: kirkdale1-279383

Watching Brief (3 February 2011)

NS 399 744 A watching brief was maintained on 3 February 2011 during the excavation of three small trenches in advance of the installation of a new handrail at the Spur Battery. There were no finds or features of archaeological significance.

Archive: RCAHMS (intended)

Funder: Historic Scotland

Kirkdale Archaeology, 2011

Information also reported in Oasis (kirkdale1-171292)

Watching Brief (22 March 2011)

NS 4001 7441 A watching brief was maintained on 22 March 2011 during the excavation of two shallow trenches for new signposts at the outer entrance to Dumbarton Castle. There were no finds or features of archaeological significance.

Archive: RCAHMS (intended)

Funder: Historic Scotland

Kirkdale Archaeology, 2011

Information also reported in Oasis (kirkdale1-171295)

Project (March 2013 - September 2013)

A project to characterise the quantity and quality of the Scottish resource of known surviving remains of the First World War. Carried out in partnership between Historic Scotland and RCAHMS.

Watching Brief (20 February 2014 - 2 April 2014)

A watching brief was maintained during excavations for the installation of a septic tank on the shore, and excavation of a sewage pipe trench within the Mason's Yard. The results of the excavations confirmed that the original (19th-century) level of the Mason's Yard was created by simply backfilling the space between the 18th-century rampart to the north and the later enclosure to the south. There was some evidence that the upper c 1.5m of the Mason's Yard boundary wall was narrower than the lower (majority) section of the wall. This may reflect a parapet level, associated with the cobbled surface.

Information from Gordon Ewart (Kirkdale Archaeology) May 2014. OASIS ID - kirkdale1-196091


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