Castle Arnold, Llangattock nigh Usk

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

There are cropmark/slight earthwork remains

NameCastle Arnold, Llangattock nigh Usk
Alternative NamesCastle Arnault; Castell Arnallt; Castell Ernallt; Castro Arnaldi
Historic CountryMonmouthshire
Modern AuthorityMonmouthshire
1974 AuthorityGwent

Castle Arnold, destroyed in 1177, is traditionally believed to be the site of the palace of Kings of Over Gwent. The visible remains at the site include a natural mound, approximately 80m east to west by 50m and up to 6.0m high set on the fringes of the Usk flood plain. A subrectangular enclosure, c.50m E-W by 26m, upon the summit of the mound, is defined by low banks on the west and east, elsewhere by steep natural slopes. Attached on the western side is a second enclosure, c.32m E-W, defined by a bank on the west. (Coflein)

The site of the stronghold of Sitsyllt ap Dyfnwal, treacherously murdered at Abergavenny Castle on Christmas Day 1175 by William de Breos. The site was then abandoned. (Glamorgan-Gwent Archaeological Trust HER)

Castell Arnallt should be reassessed as the site of an important Llys rather than a motte. (Phillips p. 103)

The monument comprises the remains of a castle mound, dating to the medieval period (c. 1066 -1540 AD). It consists of a large, long, oblong mound with relatively steep sides and a flattish top. It measures rough 87m E/W and 52m N/S, and is up to 4m high. The site is larger than a normal motte, and is likely to be natural in origin. Geophysical survey has revealed the presence of masonry structures on the summit of the mound. Historical references indicate that this was the fortified home of Seisyll ap Dyfnwal, the Welsh Lord of Gwent Uwchcoed. (Scheduling Report)

Gatehouse Comments

David Maynard kindly informs Gatehouse that "a geophysical survey was reported on in Archaeology in Wales the CBA regional journal. It didn’t really add much to the knowledge of the site, beyond confirming that there is something there."

- Philip Davis

This site is a scheduled monument protected by law

Not Listed

The National Monument Record (Coflein) number(s)
County Historic Environment Record
OS Map Grid ReferenceSO320100
HyperLink HyperLink HyperLink

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Calculate Print


  • Morgan, Gerald, 2008, Castles in Wales: A Handbook (Talybont: Y Lolfa Cyf.) p. 242 (listed)
  • 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. 103, 144-6
  • King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol. 1 p. 284
  • Bradney, J.A., 1904-33, History of Monmouthshire Vol. 1 p. 334-5


  • 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

Primary Sources


  • Maynard, David, 6-2-2007, pers. corr.
  • Phillips, Neil, 2005, Earthwork Castles of Gwent and Ergyng AD 1050-1250 (PhD Thesis University of Sheffield) Download