The first of this family upon record is Sir William de Mohun, one of the companions in arms of the Conqueror, who is stated to have had no less than 47 stout knights of name and note in his retinue at the battle of Hastings, and for the good services rendered to his royal master in that celebrated conflict, to have obtained the Castle Dunster, with 55 manors in the co. of Somerset, besides several other lordships in Wilts, Devonshire, and Warwickshire.