Morlais Castle began to be built by Gilbert de Clare around 1287 – 1288, on the northernmost boundary of his Glamorgan lordship, to extend the influence of the de Clare family on the territory of his neighbor, Humphrey de Bohun, Earl of Hereford. The name of the castle originated from a nearby river, which in the Celtic language meant mavr (great) and glais (stream).
Construction of Morlais immediately led to tension with Humphrey de Bohun. The dispute ended in 1291 with a skirmish, known as the Battle of Maes Vaynor. After this event, king Edward I intervened to solve this local, but potentially destabilizing conflict. Both Gilbert and Humphrey were fined and spent a short time in the prison at the Tower of London. Gilbert was punished with a larger fine of 10,000 marks due to the construction of the Morlais castle.
The king’s intervention stopped works on the castle and it is uncertain whether it were ever resumed. Certainly, however, the stronghold remained in use, because it was captured by the Welsh during the revolt of Madog ap Llywelyn in 1294. After the suppression of the rebellion, the castle returned to the hands of the de Clare family, but the death of Gilbert de Clare in 1295 caused the abandonment of Morlais and falling it into ruin.
The castle occupied the top of a limestone hill overlooking the Taf Fechan river, flowing on the north and west sides. The site was an Iron Age stronghold, and the earlier earthen fortifications were reinforced and incorporated into the new castle, giving it an unusual configuration. The fortifications had the shape of a pentagon, which in the northern part was divided by an internal, transverse wall to separate the upper ward. The defensive walls were very massive, up to 3 meters thick, except for the safer western curtains and the transverse wall. On the north, south and east sides, the castle was additionally surrounded by a wide dry moat carved in the rock, about 3 meters deep, located about 12-18 meters from the castle curtains. To the west, it was unnecessary because of the steep slopes of the hill.
The upper ward had a triangular layout with sides about 45 meters long and was dominated by a large round tower, protruding far in front of the perimeter on the north side. Its diameter was 18 meters. The south side of the upper was was guarded by a horseshoe tower, placed in the center of the inner curtain of the wall, and another horseshoe tower, about 10 meters in diameter, was located between the upper and lower ward, on the eastern side. It protected both the gate between two parts of the castle and the main outer gate (equipped with a portcullis). The building in the courtyard had an oblong form measuring 25 x 9 meters. It probably housed a representative great hall and was adjacent to a smaller wing, presumably of a residential nature.
The fortifications of the lower part of the castle separated a vast courtyard about 60 x 80 meters. Quite unusually, the lower ward also had a large cylindrical tower, probably of the keep type, located on the south-eastern side. It had a diameter of as much as 18 meters, with very massive walls 5 meters thick at the base. There was a passage closed with a portcullis and a pointed-arched entrance portal leading to a twelve-sided vaulted ground floor, supported by a single, massive pillar. The upper floors were accessible via a spiral staircase, reached from the entrance passage. In addition to the massive south-eastern tower, the lower ward was strengthened by four more cylindrical towers, one of which was extended far in front of the perimeter of the defensive walls to the south, in order to flank the second gate (it could also be a low bastion, not necessarily of tower character).
In the courtyard of the lower ward, near the inner faces of the defensive walls, economic and auxiliary buildings were erected. The over 20-meter-long building with thick walls on the eastern side stood out in particular. In the middle of the courtyard there was a large rainwater tank carved in the rock base.
The castle has not survived to modern times. Its layout is best seen from aerial view, only the remains of a dry moat, a water reservoir at the outer ward and small fragments of walls are visible on the ground. The most interesting element is the surviving chamber of a cylindrical keep with a preserved central pillar, vaults and an ogival entrance portal. Entrance to the castle area is free.
Kenyon J., The medieval castles of Wales, Cardiff 2010.
Salter M., The castles of Gwent, Glamorgan & Gower, Malvern 2002.
Website castlesfortsbattles.co.uk, Morlais castle.