id: sig-20260722-report-gm021
site_id: gb-dinas-powys-dinas-powis
attribute: designation_report
value: 'Reference Number

  GM021

  Name

  Dinas Powis Castle

  Date of Designation

  Status

  Designated

  Unitary Authority

  Vale of Glamorgan

  Community

  Dinas Powys

  Easting

  315275

  Northing

  171637

  Broad Class

  Defence

  Site Type

  Castle

  Period

  Medieval

  The following provides a description of the Scheduled Ancient Monument.

  The monument comprises the remains of a medieval castle. Dating to around 1200 or slightly
  earlier, it was occupied into the 13th century and possibly later. It is located at the
  southern end of a narrow ridge, with steep slopes below on all but the south-east side –
  this gave the site great natural strength.

  Only the curtain wall of Dinas Powys Castle remains standing, and much of this is ruinous;
  but from the outside the castle still has the appearance of a defensive stronghold. The
  castle has a rectangular keep measuring 18m by 13m which is reduced to rubble. The very
  ruined north-west half of the early keep stands in a thicket just beyond the north curtain
  wall. It appears to have been a typical early Norman example, rectangular, with very thick
  walls, and it extended up to and possibly slightly beyond the curtain wall. When this was
  built a doorway, now a ragged gap, was made into the keep’s basement.

  The curtain wall is straight sectioned without corner towers and encloses a roughly rectangular
  area. The main entrance on the south-east side was originally a simple round-headed archway;
  now its merely a ragged gap, with a draw bar hole on its west side. A narrow postern gate
  with a pointed arch is located in the north-east wall and there are indications that masonry
  and timber buildings including a great hall will have lined the walls. The north-east and
  north-west curtain walls are high and well preserved, with much of their facing stone still
  in place. Putlog holes are the only relieving feature in their otherwise blank surfaces.
  The south-west wall is in poor condition and has lost most of its facing stone. The south-east
  side has the only window gaps in the castle and a fine east corner with large dressed Sutton
  stone alternating quoins.

  The castle was the centre of the lordship of Dinas Powys, and was held by the Norman de
  Sumeri family certainly in the mid-12th century and possibly earlier; the lordship was probably
  acquired by Roger de Sumeri soon after the initial Norman conquest of the area.

  The monument is of national importance for its potential to enhance our knowledge of medieval
  defensive and domestic practices. The monument is well-preserved and an important relic
  of the medieval landscape. It retains significant archaeological potential, with a strong
  probability of the presence of both structural evidence and intact associated deposits.

  The scheduled area comprises the remains described and areas around them within which related
  evidence may be expected to survive.'
source_url: http://cadwpublic-api.azurewebsites.net/reports/sam/FullReport?lang=en&id=1025
source_title: Scheduled Monument Full Report — Dinas Powis Castle
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.