Grosmont Castle

Has been described as a Possible Timber Castle (Motte), and also as a Possible Masonry Castle

There are major building remains

NameGrosmont Castle
Alternative NamesGrismond; Grossemont; Grismont; Grossomonte
Historic CountryMonmouthshire
Modern AuthorityMonmouthshire
1974 AuthorityGwent

Grosmont Castle was one of a trio of earth-and-timber strongholds built by the Normans in the aftermath of the Conquest to guard the communication route between Hereford and Wales, together with Skenfrith Castle (NPRN 93431) and White Castle (NPRN 94853). It lies within a wide moat (20m across), and a further second enclosure defined by scarps and ditches. From the thirteenth century the site was re-built in the more durable local red sandstone, and timber defences were replaced by a stone curtain wall, protected by three circular towers and a gatehouse; a similar design to that of Cilgerran Castle (NPRN 95037). In the following century the buildings around the inner ward were remodelled to suit a noble household. The castle was attacked and besieged by Gruffudd, son of Owain Glyndwr in 1405, before being relieved by a force from Hereford. By 1538 Grosmont was disused and abandoned. It came into state care in 1923. (Coflein–ref. Knight, 2000)

First castle on site in existence by 1154, which consisted of wooden buildings defended by a palisade and ditch, but only the moat remains of this earliest period. The masonry castle was built in 3 main periods. The Great Hall is the earliest structure, dating from about 1210. The second building period, during the first half of the C13th, saw the enclosure of the inner ward, with a stone curtain flanked by 3 semi-circular towers and a projecting gatehouse. The final stage, probably around 1330, included the addition of a range of rooms outside the N curtain and the enlargement and heightening of the SW tower.

The stone castle stands on a roughly rectangluar platform surrounded by a ditch 6m deep. The remains of a probable bailey encircling the castle can be traced on the SE and NE as a scarped slope 4m high, and on the N as 2 banks 0.3m high and 9m wide with an intermediate ditch 1m deep

(Glamorgan-Gwent Archaeological Trust HER)

On a flat elevated plateau, some 100m NW of Grosmont village, approached along a narrow lane from the main street.

Following the initial conquest of the Welsh kingdom of Gwent by William Fitz Osbern, Lord of Breteuil in Calvados, between 1067-75, the Normans built a triangle of castles - Grosmont, Skenfrith and White Castle - to control their newly won lands. These late C11 defences would have been of earth and timber. At Grosmont the great ditch of that ringwork castle still survives, the perimeter of which would originally have been protected by a wooden palisade and timber gate tower. In July 1201, King John granted the three castles to Hubert de Burgh, who completely rebuilt Grosmont in stone, beginning with the rectangular hall-block (1201-4). Work stopped in 1205 after Hubert was captured whilst fighting for King John in France. Whilst he was still prisoner John granted the three castles to William de Braose of Abergavenny, in royal favour at the time. A prolonged dispute over the ownership of the castles then ensued, but in December 1218 this was settled by the King's Court in Hubert's favour. Hubert regained possession of Grosmont and between c1219-1232 embarked upon a major rebuilding programme, replacing the timber defences by a stone curtain wall with round towers at the angles, in the defensive style of the early C13. During the C14, the Earls of Lancaster carried out various alterations to Grosmont. The buildings around the inner ward were remodelled c1330 (either by Henry of Lancaster or his son, Henry of Grosmont) and alterations were made to the northern chamber block, including the addition of an elegant octagonal chimney shaft, and to the gatehouse which was extended to incorporate a drawbridge. The last fighting at Grosmont took place during the war of Owain Glyndwr, who attacked Gwent during the summer of 1404, but was defeated at the battle of Campston Hill. In 1825 the Duchy of Lancaster sold the ruins to the Duke of Beaufort and in 1923 they were given to the state by Mrs Frances Lucas-Scudamore.

C20 wooden bridge gives access to inner ward of castle, the surviving ruins are built of local red sandstone rubble and ashlar, and form the complete ground-plan of the castle with hall block to east and curtain wall to west. Much of SW tower of the curtain wall stands, but few remains of gatehouse survive. Hall Block, originally two-storeys with upper hall. Raking plinth, west corners have ashlar quoins. Ground-floor has tall, narrow lancets: four in each of the long walls, one in the NW wall and two on SE side. The interior shows that the taller, corresponding lancets at first-floor level were originally set in wide segmental headed openings. Two of these survive, either side of the hall fireplace at S end. Below, a stone spiral stair (formerly linking ground-floor with upper hall) is set in an embrasure in left corner. In centre of hall block are remains of a stone partition wall, probably dating from the remodelling of c1219. SW Tower once formed one of three round towers of the C13 curtain wall, but in C14 the rear facade was rebuilt and enlarged. This courtyard front is buttressed with a tall pointed entrance arch on ground floor and, above, a single opening at first and second floor levels. Interior has deep circular basement, ground-floor chamber has three archers loops in splayed embrasures with two-centred arched heads. Access to upper floors, largely rebuilt in C14, is by spiral stair to right of entrance arch. First floor has three windows in arched recesses facing west. Each of the floors has a fireplace on the NW wall, including upper floor fireplace with chamfered jambs. Northern Block was built on site of third tower of C13 curtain wall, demolished when C14 block was built. The most notable surviving feature of this building is the elegant octagonal chimney with slender shaft rising from a raked and moulded base to delicately worked trefoil headed gablets on each face and a coronet-like top above. (Listed Building Report)

The early hall at Grosmont was most probably built within forty years either side of 1110. It still stands two stories high and has many features of comfort within its walls. There are many reasons to believe that this hall was built early in the castle’s history for the evidence points clearly to Grosmont castle having been fortified in stone from the first. Who actually first built the castle though, is more of a problem. Both the first earls of Hereford and Pain Fitz John had a great deal of wealth and ruled Gwent at a time when the stable rule of the Normans in Wales seemed inevitable. Grosmont hall is certainly not a fortress. It was built as the administrative centre of a barony with both comfort and administration in mind. White Castle to the west, however, was built as a fortress from the first, probably in concert with the foundation of Grosmont. Orcop to the east, a true motte and bailey castle, may be older. (Remfry)

Gatehouse Comments

The castle has been said to be raised on an earlier motte but Phillips states this supposed 'motte' was collapsed masonry and the castle was a new build masonry castle of the late C12/early C13 although the documentary evidence suggests some sort of manorial centre here before that time.

- Philip Davis

This site is a scheduled monument protected by law

This is a Grade 1 listed building protected by law

Historic Wales CADW listed database record number
The National Monument Record (Coflein) number(s)
County Historic Environment Record
OS Map Grid ReferenceSO405244
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Copyright Philip Blayney All Rights Reserved
Copyright Philip Blayney All Rights Reserved
Copyright Philip Blayney All Rights Reserved
Copyright Philip Blayney All Rights Reserved
Copyright Philip Blayney All Rights Reserved
Copyright Philip Blayney All Rights Reserved
Copyright Philip Blayney All Rights Reserved
Copyright Philip Blayney All Rights Reserved

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  • Kenyon, John, 2010, The Medieval Castles of Wales (University of Wales Press) p. 141-145
  • Remfry, P.M., 2008 (rev. edn.), Grosmont Castle and the families of Fitz Osbern, Ballon, Fitz Count, Burgh, Braose and Plantagenet of Grosmont (Castle Studies Research & Publishing)
  • Morgan, Gerald, 2008, Castles in Wales: A Handbook (Talybont: Y Lolfa Cyf.) p. 180-6
  • Griffiths, R.A., 2008, 'Lordship and Society in the Fifteenth Century' in R. Griffiths, T. Hopkins and R. Howell (eds), The Gwent County History (Cardiff: University of Wales Press) Vol. 2 The Age of the Marcher Lords, c. 1070-1536 p. 241-79
  • Courtney, P., 2008, 'The Marcher Lordships' in R. Griffiths, T. Hopkins and R. Howell (eds), The Gwent County History (Cardiff: University of Wales Press) Vol. 2 The Age of the Marcher Lords, c. 1070-1536 p. 51-3 (tenurial history)
  • Kenyon, J.R., 2008, 'Masonry Castles and Castle-building' in R. Griffiths, T. Hopkins and R. Howell (eds), The Gwent County History (Cardiff: University of Wales Press) Vol. 2 The Age of the Marcher Lords, c. 1070-1536 p. 89-114
  • Prior, Stuart, 2006, A Few Well-Positioned Castles: The Norman Art of War (Tempus) p. 110-164
  • Phillips, Neil, 2006, Earthwork Castles of Gwent and Ergyng AD 1050-1250 (British Archaeological Reports) p. 203-5
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  • Pettifer, Adrian, 2000, Welsh Castles, A Guide by Counties (Boydell Press) p. 130-1
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  • Remfry, Paul, 1995, Grosmont Castle, 1066 to 1538 (SCS Publishing: Worcestershire)
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  • King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol. 1 p. 283
  • Fry, P.S., 1980, Castles of the British Isles (David and Charles) p. 355
  • Renn, D.F., 1973 (2 edn.), Norman Castles of Britain (London: John Baker) p. 196
  • Colvin, H.M., Brown, R.Allen and Taylor, A.J., 1963, The history of the King's Works Vol. 2: the Middle Ages (London: HMSO) p. 657-8
  • Oman, Charles W.C., 1926, Castles (1978 edn Beetham House: New York) p. 159-163
  • Bradney, J.A., 1906, History of Monmouthshire Vol. 1.1 p. 70-2
  • Mackenzie, J.D., 1897, Castles of England (Heinemann) Vol. 2 p. 82-3 online copy
  • Bagnall-Oakley, M.E., 1896, Papers on Monmouth Castle etc. (Mon. and Caerleon Ant. Ass) p. 81-5, 89
  • Clark, G.T., 1884, Mediaeval Military Architecture in England  (Wyman and Sons) Vol. 2 p. 51-3 (reprint of 1867 article) online copy
  • Coxe, W., 1801, An Historical Tour in Monmouthshire (London) Vol. 2 p. 326-7, 334-5
  • Buck, Samuel and Nathenial, 1774, Buck’s Antiquities (London) Vol. 1 p. 186


  • William Camden, 1607, Britannia hypertext critical edition by Dana F. Sutton (2004)
  • Chandler, John, 1993, John Leland's Itinerary: travels in Tudor England_ (Sutton Publishing) p. 225
  • Toulmin-Smith, Lucy (ed), 1910, The itinerary of John Leland in or about the years 1535-1543 (Bell and Sons; London) Vol. 2 p. 71 online copy


  • Guy, Neil et al, 2008/9, 'Grosmont Castle' Castle Studies Group Journal Vol. 22 p. 26-30 (slight)
  • Knight, J.K.., 1978, 'Grosmont Castle' 125th Annual Meeting in Gwent and the Forest of Dean 1978 CAA p. 22-3
  • Craster, O.E. (and Talbot), 1967, 'Skenfrith Castle: When was it built?' Archaeologia Cambrensis Vol. 116 p. 134
  • Hogg, A.H.A. and King, D.J.C., 1967, 'Masonry castles in Wales and the Marches: a list' Archaeologia Cambrensis Vol. 116 p. 71-132
  • Hogg, A.H.A. and King, D.J.C., 1963, 'Early castles in Wales and the Marches: a preliminary list' Archaeologia Cambrensis Vol. 112 p. 77-124
  • Brown, R, Allen, 1959, 'A List of Castles, 1154–1216' English Historical Review Vol. 74 p. 249-280 (Reprinted in Brown, R. Allen, 1989, Castles, conquest and charters: collected papers (Woodbridge: Boydell Press) p. 90-121) view online copy (subscription required)
  • Faulkner, P.A., 1958, 'Domestic Planning from the Twelfth to the Fourteenth Centuries' The Archaeological Journal Vol. 115 p. 150-83 online copy
  • Roderick, A.J. and Rees, W., 1954, 'The Lordships of Abergavenny, Grosmont, Skenfrith and White Castle: Accounts of the Ministers for the year 1256-57' South Wales and Monmouth Record Society Publications Vol. 3 p. 22-47
  • Roderick, A.J. and Rees, W., 1553, 'The Lordships of Abergavenny, Grosmont, Skenfrith and White Castle: Accounts of the Ministers for the year 1256-57' South Wales and Monmouth Record Society Publications Vol. 2 p. 68-125
  • Benn, C.A., 1941, 'Castles Mentioned in the Pipe Rolls Under Herefordshire' Transactions of the Woolhope Naturalists' Field Club p. 130
  • Bagnall-Oakley, M.E., 1909, Archaeologia Cambrensis Vol. 3 p. 103-5
  • Bagnall-Oakley, M.E., 1895-97, 'Grosmont Castle, Skenfrith Castle and Church, Pembroke Castle' Transactions of the Bristol and Gloucestershire Archaeological Society Vol. 20 p. 88-99 online copy
  • Banks, R.W., 1876, 'The castles of Grosmont, Skenfrith and Whitecastle' Archaeologia Cambrensis Vol. 31 p. 304-6 online copy
  • Clark, 1867, The Builder Vol. 25 p. 274

Guide Books

  • Knight, Jeremy K., 2009 (Rev.edn), The Three Castles: Grosmont Castle, Skenfrith Castle, White Castle and Hen Gwrt medieval moated site (Cardiff: CADW)
  • Knight, Jeremy K., 2000 (2edn), The Three Castles: Grosmont, Skenfrith and White Castle (Cardiff: CADW)
  • Knight, Jeremy K., 1987, The Three castles: Grosmont, Skenfrith and White Castle (Cardiff: CADW)
  • Knight, Jeremy K., 1980, Grosmont Castle, Gwent/ Castell y Grysmwnt (HMSO)
  • Radford, C.A.R., 1946, Grosmont Castle (HMSO)

Primary Sources

  • Pipe Rolls 1163, 1183, 1184, 1186, 1199, 1201, 1205, 1206 (see Pipe Roll Society for references)
  • Cronne, H.A. and Davis R.H.C. (eds), 1968, Regesta Regum Anglo-Normannorum, 1066–1154 Vol. 3 Regesta regis Stephani ac Mathildis imperatricis ac Gaufridi et Henrici ducum Normannorum, 1135-54 p. 119 No. 314 online copy
  • Brut y Tywysogion c. 1215 (Several transcriptions and translations exist the best being Jones, T., 1952, Brut Y Twysogion (University of Wales, History and Law series 11)–based on the Peniarth MS 20 version. There is a flawed translation Williams ab Ithel, John, 1860, Brut Y Twysogion or The Chronicle of the Princes (Rolls Series) online copy)
  • Hardy, T.D. (ed), 1835, Rotuli litterarm patentium in Turri londinensi asservati (Record Commission) p. 57, 194 online copy
  • Maxwell Lyte, H.C. (ed), 1903, Calendar of Charter Rolls Henry III 1226-1257 Vol. 1 (HMSO) p. 74 (Grant to John de Braos in 1228) online copy
  • Maxwell Lyte, H.C. (ed), 1903, Calendar of Patent Rolls Henry III (1225-32) Vol. 2 p. 502 online copy
  • 1906, Calendar of Patent Rolls Henry III (1232-47) Vol. 3 p. 2, 58, 445 online copy
  • Giles, J.A. (ed), 1849, Roger of Wendover, Flowers of History (London: Henry G. Born) Vol. 2 p. 573 online copy
  • Nicolas, H. (ed), 1834, Proceedings and Ordinances of the Privy Council of England Vol. 1 p. 248-50
  • Rickard, John, 2002, The Castle Community. The Personnel of English and Welsh Castles, 1272-1422 (Boydell Press) (lists sources for 1272-1422) p. 312-3
  • DL44/95 (Survey of 5 Elizabeth) The National Archives reference
  • SP14/49/82 (Survey of 1609) The National Archives reference


  • Phillips, Neil, 2005, Earthwork Castles of Gwent and Ergyng AD 1050-1250 (PhD Thesis University of Sheffield) Download