William de Mohun of Dunster, 1st Earl of Somerset William de Mohun of Dunster, 1st Earl of Somerset William de Mohun of Dunster, Earl of Somerset (c. 1090 – c. 1155), 2nd feudal baron of Dunster, was a favourite of Empress Matilda and a loyal supporter of her in the war against King Stephen, during which he earned the epithet of the "Scourge of the West". William was the son of William de Moion, who was seigneur of Moyon which is close to Saint-Lô. The elder William was High Sheriff of Somerset in 1084. During the war between Matilda and Stephen, Stephen marched against Mohun's castle at Dunster, but
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,