Castell Du

Castell Du stands in a quiet stretch of the Brecon Beacons, eight miles west of Brecon in Powys. Welsh sources call it ‘black castle’, while English records know it as Sennybridge Castle or Castell Rhyd-y-Briw. Llywelyn ap Gruffudd, Prince of Wales, is thought to have ordered its construction in the 1260s. A single document from 1271 mentions a fort at Rhyd-y-Briw, matching the site. By the late 13th century the castle had vanished from records, probably taken by Edward I’s forces in 1276–77 and then left to decay. The remains are small but striking. A D-shaped tower still rises above the grass, and two more towers may lie beneath Second World War pill-boxes. Archaeologists have yet to uncover the full plan, so every stone tells part of the story. The setting is peaceful farmland today, yet the earthworks still hint at past battles. The castle’s brief life shows how quickly power shifted in medieval Wales. Visitors walk a farm track to the low mound where the ruins stand. The D-shaped tower is the main landmark, its curved wall weathered by centuries. Pill-boxes from the 1940s sit nearby, a reminder of more recent use. The surrounding fields stretch to the hills, giving a sense of isolation. The site is quiet, with only the wind and birds for company.