Description

The monument comprises the remains of a medieval castle occupying an almost vertically sided igneous outcrop overlooking and immediately to the east of the early medieval boundary earthwork Offa's Dyke. There are few signs of artificial defences other than possible scarping on the one approach to the S but the remains of a masonry curtain wall and the bases of at least two round towers have been identified near the edge of the summit. Running around the base of the rock and broadening to the E and N is a partly wet ditched oval enclosure. This has been assumed to form a bailey or lower court but has not been archaeologically investigated. Nantcribba lay at the western extremity of lands held by the Corbet family of Caus Castle in Shropshire and has been identified as the castle of Gwyddgrug, first mentioned in 1242 and taken by Gruffudd ap Gwenwynyn of Powys in 1263.

The monument is of national importance as a documented medieval castle with potential to enhance our knowledge of medieval defensive and domestic architecture and associated material culture. It forms an important relic of the broader medieval landscape, particularly with the adjacent Offa's Dyke and shares group value with a dense concentration of minor Marcher castles in the Vale of Montgomery. It is an unusual example of its class, the strong site, superficially resembling an unconventional motte and bailey whilst its relationship to the Dyke raises the possibility of an earlier settlement or defensive site. It is one of a series of 13th century Welsh, Marcher and Royal stone castles constructed in spectacular locations at the edge of territorial boundaries and its site is likely to have been chosen as much as a statement of lordship and military strength as much as for its strong defensive qualities. It has high archaeological potential and is likely to retain structural remains and intact associated deposits containing artefactual and environmental evidence of its construction, development, use and the contemporary landscape.

Source: Cadw