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 Avill, offering a natural defence and making the village an inland port. Nearby is the Dunster Park and Heathlands Site of Special Scientific Interest noted for nationally important lowland dry heath, dry lowland acid grassland, wood-pasture with veteran trees and ancient semi-natural oak woodland habitats. The fauna of the lowland heath includes the heath fritillary ("Mellicta athalia"), a nationally rare butterfly. The assemblage of beetles associated with the veteran trees is of national significance because of the variety and abundance of species. Along with the rest of South West England, Dunster has a temperate climate which is generally wetter and