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 a keen historian, decided to follow this trend at Dunster; in the process, he also hoped to accommodate the larger household and facilities required for a 19th-century landowner: by 1881, the castle required 15 "living-in" servants alone. He employed Anthony Salvin, a noted architect then most famous for his work at Alnwick Castle, to carry out the work between 1868 and 1872 at a total cost of £25,350 (equivalent to £1.76 million in 2010). The work included the construction of an underground reservoir, holding of water to provide running water for the castle and village. Salvin aimed to create a