From Cardiff: Three Castles & the Welsh Mountains

Head north from Cardiff into the South Wales valleys. The guide introduces the Norman and Plantagenet colonisation of Wales — the systematic castle-building programme that began with William the Conqueror and intensified under Edward I — and explains why Gilbert de Clare, Earl of Gloucester, chose the Caerphilly basin as the site for the most ambitious water fortress in medieval Britain.

Caerphilly Castle (Castell Caerffili) was built with extraordinary speed between 1268 and 1271 by Gilbert de Clare in direct response to Llywelyn ap Gruffudd's growing domination of Wales. At 30 acres it is the second largest castle in the UK after Windsor, and the largest in Wales — its scale achieved not by height but by water. Three artificial lakes, two moats, and a vast concentric ring of walls and towers transform the valley floor into a fortress that cannot be approached on any side without crossing water. The famous leaning southeast tower — which leans at a greater angle than the Tower of Pisa — was deliberately undermined during the Civil War and never restored, becoming one of the defining images of Welsh castle architecture.

Tretower, in the Usk valley above Crickhowell, offers something unique on the Welsh castle landscape: a complete Norman round tower (c. 1230) standing immediately beside the fortified manor court built in the 14th and 15th centuries by the Picard and Vaughan families. The court's great hall, solar, and gatehouse date from the 1420s to 1480s — the same period as Raglan — and preserve the transition from purely military architecture to the comfortable defended manor that represents the end of the medieval castle tradition. The Brecon Beacons rise directly above the site.

Raglan Castle was built from 1431 by Sir William ap Thomas — 'the Blue Knight of Gwent' — and completed by his son William Herbert, the most powerful man in Wales in the 1460s. Its distinguishing feature is the Yellow Tower of Gwent (Great Tower): a hexagonal keep surrounded by its own water-filled moat, accessible only by a drawbridge from the main castle — a castle within a castle. Raglan was one of the last great medieval castle-building projects in Britain, conceived as both a military fortress and a grand noble residence. In 1646 it was the last Royalist stronghold in Wales to surrender to Parliamentary forces after a three-month siege. Parliament subsequently ordered the slighting of the Great Tower; its walls were undermined and partially demolished, creating the dramatic ruin visible today.