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 a keen historian, decided to follow this trend at Dunster; in the process, he also hoped to accommodate the larger household and facilities required for a 19th-century landowner: by 1881, the castle required 15 "living-in" servants alone. He employed Anthony Salvin, a noted architect then most famous for his work at Alnwick Castle, to carry out the work between 1868 and 1872 at a total cost of £25,350 (equivalent to £1.76 million in 2010). The work included the construction of an underground reservoir, holding of water to provide running water for the castle and village. Salvin aimed to create a