id: sig-20260722-report-cm029 site_id: gb-llandeilo-dinefwr attribute: designation_report value: 'Reference Number CM029 Name Castell Dinefwr Date of Designation Status Designated Unitary Authority Carmarthenshire Community Llandeilo Easting 261203 Northing 221739 Broad Class Defence Site Type Castle Period Medieval The following provides a description of the Scheduled Ancient Monument. This monument comprises the remains of a medieval castle probably built by Rhys Gryg (d. 1233), son of Rhys ap Gruffudd. Situated upon a rocky crag with commanding views over the wide Tywi Valley, this location is characteristic of Welsh-built stone castles in the early years of the thirteenth century. The castle was of paramount importance in Welsh history as the seat of the Welsh rulers of Deheubarth, the medieval principality of south-west Wales. There is nothing in the surviving archaeological evidence to argue for or against there having been a fortification on the site before the time of Rhys ap Gruffud (d. 1197), and the present defensive layout was probably first adopted in his time. By the later twelfth century, two enclosures stood side by side along the rock crag, defined on three open sides by a deep rock-cut ditch. Buildings within the defences would have been of timber or stone, but their form remains unknown. What survives in terms of upstanding remains dates largely from the thirteenth century and was the work of Rhys ap Gruffudd’s heirs and successors. The castle consists of an outer ward, inner ward, substantial keep, hall and other buildings. The approach to the castle is from the east - the outer ward being accessed via an outer gate. It is divided into upper and lower terraced areas, a defensive bank and deep rock-cut ditch enclose the lower part of the hilltop. This is where the castle’s domestic and service buildings such as, perhaps, the stables, smithy and bakehouse were sited. The path continues through the fragmentary remains of a middle gate and a long, narrow entrance passage protected by a high wall to the inner gate. Despite considerable alteration during several building phases, the joints of the original, large entrance arch can still be seen in the masonry. Inside the inner ward, only the foundations of the gatehouse survive. The inner ward is enclosed by a high, angular curtain wall. Dominating the interior of the castle is the great round keep on the east, with its battered base and heavy roll-moulded string course. The present ground-floor entrance is a later insertion, and the original door was on the first floor. This is now blocked by the later arched bridge leading from the steps. A trapdoor in the floor probably provided the sole access to the large, dark basement. It is now difficult to know now how much taller the keep would have been before it was so drastically modified by the addition of the later summer-house on the top, but it may well have had at least one further storey. The summer-house, with its conical roof, became a famous landmark, and it still retains its door and large windows designed to give splendid views over Dinefwr Park. The curtain wall probably continued around the keep on the east but has now fallen, and the walling on the north-east corner is modern. The circular three-storey tower on the north was probably constructed after 1277. It has a latrine on the west side, and a deep basement. The tower and the adjacent rectangular hall, the inner wall of which has now fallen, were substantially modified in the early Tudor period. Of unknown date are the (probably) timber buildings which evidently lay against the curtain wall on the west. Built into the wall on the south is a latrine chamber with a corbelled roof, and adjacent to the gatehouse is a small turret which was transformed into another summer-house in the 18th century. The Welsh town of Dinefwr lay in the immediate vicinity of the castle; its precise position is uncertain, though the flat ground just to the north of the castle is a distinct possibility. By the time of the Welsh Wars of Edward I (1276-77 and 1282-83), the castle was already a formidable fortress. However, in 1287 the castle was captured by the English. From the late thirteenth through to the fifteenth century, the castle served as a centre of royal authority and administration. Repairs and new building occasionally featured to a greater or lesser extent during this period. Subsequently Dinefwr was to see a new lease of life in the late seventeenth and eighteenth centuries. The top of its keep was converted to a summerhouse as artists, poets and tourist began to visit in search of the Picturesque and Romantic. The monument is of national importance for its potential to enhance our knowledge of medieval social, domestic and political life and warfare. The scheduled area comprises the remains described and an area around them within which related evidence may be expected to survive.' source_url: http://cadwpublic-api.azurewebsites.net/reports/sam/FullReport?lang=en&id=678 source_title: Scheduled Monument Full Report — Castell Dinefwr publisher: Cadw observed_date: '2026-07-22' collected_by: scripts/build_assessment_batch.py confidence: high notes: The designation text. Assess the six bands against THIS evidence only; omit any band it does not speak to.