South Wales was conquered by Robert Fitzhamon, the Baron of Gloucester, at the end of the eleventh century. The conquered lands included, among others, Llanblethian, which Robert granted to Herbert de St Quentin around 1102. Herbert is considered to be the creator of the first timber and earth fortifications, then expanded at the end of the 12th century. The castle remained in the St Quentin family until 1233, when it was taken over by Richard Siward. The new owner, however, was declared outlawed in 1245, and Llanblethian went to Richard de Clare, Earl of Gloucester. His grandson, Gilbert de Clare, began a major reconstruction of the castle around 1307, but he died in the Battle of Bannockburn in 1314, and work on the probably unfinished castle was interrupted. In 1317 Llanblethian was granted to Hugh Despenser and kept by his family even after the fall of the king’s favorite. Until the 15th century, the castle’s gatehouse was used as a local prison. In the eighteenth century, the castle was already largely ruined, but the rooms on the ground floor of the gatehouse were transformed into a residential house, which was used until the 19th century.
The primary building had the form of a closed, timber-earth circuit of the fortifications (ringwork). It was erected on a hill overlooking the bend of the River Thaw, which provided a strong, natural defense from the north, west and south, due to steep riverside escarpments. At the end of the 12th century, a quadrilateral keep was built on the hilly terrain.
In the fourteenth century, the keep was surrounded by a stone defensive wall on the plan of an irregular quadrangle, creating a large inner ward. The entrance to the castle was provided from the east by a huge gatehouse, consisting of two polygonal towers flanking the passage between them. It was reinforced with two portcullises, two doors and had two side guard’s rooms, each with four arrowslits. The northern room was a little smaller because there was a staircase upstairs. The upper storey had only one room warmed by a fireplace, although there could be wooden partition walls. There was a latrine in the south-west corner. There is little known about the appearance of the second floor, probably there were living quarters. An additional defense of the castle was provided by a rectangular north-east tower and a polygonal south-east tower. A much smaller, semicircular turret occupied the north-west corner of the castle.
Until today, the eastern gatehouse without the highest storey has survived, fragments of defensive walls of a small height and fragments of walls in the place of the former keep. Entrance to the castle area is free.
Kenyon J., The medieval castles of Wales, Cardiff 2010.
Website castlesfortsbattles.co.uk, St Quintin’s Castle.