A motte-and-bailey castle is thought to have previously occupied the site of Llawhaden Castle and the present structure was built by the bishops of the Diocese of St David in the 13th century. The castle was abandoned in the 16th century and some of the stone was removed for local building projects. The site is privately owned by the Lord of the Manor of Llawhaden and managed by Cadw.
The remaining ruins date from the early 13th century. It is surrounded by a ditch, which was designed to be only crossable by a drawbridge. The castle is pentagonal in shape and while the north-western and western sides of the castle are no longer present, the other three sides remain. The gatehouse is located on the southern side, which is formed of two drum towers and a gateway. This was also where the drawbridge would have been located to allow entrance to the interior of the castle.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.