 The only remaining visible signs of the old castle are the large mound of the motte, and traces of the wall that surrounded the bailey.Twthill castle was built to a 'motte and bailey' design and was erected by Robert of Rhuddlan in 1073.He was a kinsman of Hugh d'Avranches, Earl of Chester and the castle was designed to consolidate Norman advances into the north of Wales at the command of William the Conqueror.