From the 11th century onward, the castle has served as a hereditary stately home to several families (with a few and brief reversions to the Crown) and is currently the principal seat of the Duke of Norfolk and his family (grid referenceTQ019074).
The Norman castle was built in 1068 during the reign of William I as a fortification for the River Arun and a defensive position for the surrounding land. The original structure was a Motte and Bailey castle before undergoing an extensive renovation which enlarged the motte and improved the defences. Roger de Montgomery is believed to have been declared the first Earl of Arundel when William I granted him the property as part of a much larger grant of hundreds of manors. (For other reasons, the generally accepted first creation of the title Earl of Arundel lies in the year 1138 with William d'Aubigny, confirmed in 1155).