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 Conygar Tower, was constructed by architect Richard Phelps to improve the view from the castle, and a larger park of 141 hectares (348 acres) was built just to the south of the castle, requiring the eviction of a number of tenant farmers. Henry's son, John, inherited the castle in 1780, but when his son, also called John, inherited in 1816 he chose to live in London instead, opening up Dunster Castle to the public. By 1845 the castle appeared to visitors to be past its prime: with only two of John's sisters living there and no horses or hunting dogs