Dunster Castle motte, or Upper Ward, and an area below shaped to form the bailey, or Lower Ward. Somerset became more stable in the aftermath of the post-invasion period and the unsuccessful 1068 rebellion against Norman rule. It was common in the period for the Normans to build religious houses to accompany major castles, and accordingly William de Mohun endowed a Benedictine priory at Dunster in 1090, along with its parent abbey at Bath. The River Avill was important for trade; the region around Dunster was rich with fisheries and vineyards, and Dunster Castle prospered. Stone fortifications were built on the site
Dunster Castle designated by English Heritage as a Grade I listed building and Scheduled Ancient Monument. The castle has required continuing maintenance work, in particular to its roof, itself an important historical feature. Efforts have been made to gradually redecorate the castle in a period style, using reproductions of original wallpapers and materials. The National Trust installed solar panels behind the battlements on the roof in 2008 to provide electricity and make the premises more environmentally friendly. This was the first time the National Trust have taken this approach to a Grade I listed building, and it is expected to save 1,714