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 Castle At the end of the 14th century the de Mohuns sold the castle to the Luttrell family, who continued to occupy the property until the late 20th century. The castle was expanded several times by the Luttrell family during the 17th and 18th centuries; they built a large manor house within the Lower Ward of the castle in 1617, and this was extensively modernised, first during the 1680s and then during the 1760s. The medieval castle walls were mostly destroyed following the siege of Dunster Castle at the end of the English Civil War, when Parliament ordered the defences to