As part of the works to build an extension to Plas Crug Primary School in Aberystwyth, an archaeological watching brief has revealed a fascinating structure, which was actually under the existing school building.
Historical documents (Brut y Tywysogion) dating back to the twelfth century talk about storming and burning a castle called ‘Aber-rheidol in 1164. Although we don’t know where this castle was, we thought it might have been on the site of Plas Crug School. The school is close to the mouth of the Rheidol River, between Llanbadarn Fawr and the medieval town of Aberystwyth, as described by the documents.
Before the school was built, there was a farmstead on the site, and there are lots of paintings, drawings and early photographs to show what it looked like. It was a fortified mansion, with a square tower. The tower was quite famous during the late eighteenth and early nineteenth centuries, and was an attraction for people sightseeing in the area. They describe a ruined, fortified building on an outcrop overlooking the floodplain of the river. Their drawings and paintings show battlements on the top of the tower, and the entrance on the first-floor entrance. These are features we would expect in a medieval building, possibly even going back to the twelfth century. On the other hand, it might have been built or rebuilt during the later eighteenth century by the Powells of Nanteos as a folly. By the end of the eighteenth century, it had been incorporated into a farmhouse.
We found two quite substantial walls and part of a third wall, forming three sides of a square building. They might have been built in the medieval period, as the stones look as though they were bonded with clay, which is typical of medieval structures. However, mortar in some parts of the wall appears to be of quite a late type, showing that the walls were rebuilt much later. We were able to dig to check the width of one of the walls, and it was found to be 0.82m thick. The building originally had a cobbled floor, though later on a concrete floor had been laid on top. It appeared to have been used at least into the nineteenth century, as the walls had been covered in plaster on top of an earlier layer of whitewash. There was also an iron boiler in the corner of the room.
Having finished the excavations, we think that the walls we found are the base of the tower. It seems to have medieval origins, but was extensively rebuilt at a later date, and we still don’t know whether its appearance in the paintings and drawings is how it looked in the Middle Ages.