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 prosperity of Dunster was based on the wool trade, with profits helping to pay for the construction of the tower of the Priory Church of St George and provide other amenities. The 15th century Gallox Bridge was one of the main routes over the River Avill on the southern outskirts. The market was held in "The Shambles" however these shops were demolished in 1825 and now only the Yarn Market remains. Dunster Beach, which includes the mouth of the River Avill, is located half a mile from the village, and used to have a significant harbour, known as Dunster Haven,