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
Feudal barony of Dunster who was a "powerful personage" due to her large Wyndham dowry, purchased Dunster Priory following the Dissolution of the Monasteries, which thenceforth descended with the castle. By his wife Margaret Wyndham he had children including three sons: Sir John Luttrell (died 1551), of Dunster Castle, eldest son and heir. He was one of the principal commanders in the Scottish war under the earl of Hertford. In 1545 he was knighter after the capture of Leith. He was taken prisoner by the Scots in 1550 at Broughty Craig and was ransomed for £400. He married Mary Ryce, daughter of Sir Griffith