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 designated by English Heritage as a Grade I listed building and Scheduled Ancient Monument. The castle has required continuing maintenance work, in particular to its roof, itself an important historical feature. Efforts have been made to gradually redecorate the castle in a period style, using reproductions of original wallpapers and materials. The National Trust installed solar panels behind the battlements on the roof in 2008 to provide electricity and make the premises more environmentally friendly. This was the first time the National Trust have taken this approach to a Grade I listed building, and it is expected to save 1,714