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
Feudal barony of Dunster War he made Dunster Castle available for use as a convalescent home by the Royal Navy. On the death of his father in 1944 the payment of a large sum in Death Duties left the estate indebted and uneconomic to operate, and Geoffrey, whilst reserving a tenancy for himself at the Castle, sold the estates to a property development company which sold them on to the Commissioners of Crown Lands. He bought back the Castle and grounds in 1954 and opened them to the paying public. He died in 1957 and his widow remained at the Castle until her death