Ogmore Castle construction might have begun in 1106. It was in use until the 19th century for a range of purposes, including a court of justice and a prison, but is now a substantial set of remains and a local landmark.
The earthworks were steeply banked and oval in shape, enclosing an area of 50 m in length by 35 m in width. The inner ward was flat and constructed of timber structures. After completion of the ringwork, the building material was stone. The windows were round-headed with Sutton stone ashlar. The first-floor great hall had an ornate fireplace.
William's son Maurice is credited with building the oblong keep; it is perhaps the oldest Norman keep in Glamorgan. Situated north of the main gateway, the keep was the first masonry building and was probably built in the 1120s. It is both the castle's tallest surviving building, and one of the oldest buildings in South Wales. Though only three of the original walls survive, their structure is characterized by irregularly shaped field stones, glacial pebbles, Lias limestone slabs, and brown mortar. Thomas de Londres replaced a timber palisade with a stone wall in around 1200.
In the early 13th century, a second storey was added that housed private apartments. Garderobes were featured on two levels and a latrine tower was part of the exterior. A well-preserved lime kiln was built over an indeterminate 13th-century structure. Subsequently, a courthouse dating to the 14th century and rebuilt in the mid-15th century, was probably the third building to occupy the same spot. The building was rectangular in shape with a simple doorway and was flanked by two chambers. Having sustained damage during Owain Glyndŵr's revolt, a new courthouse, situated in the castle's outer bailey, was built in 1454 and was in use until at least 1631.
The present-day castle remains consist of the keep and some outer walls.
The Château de Foix dominates the town of Foix. An important tourist site, it is known as a centre of the Cathars. Built on an older 7th-century fortification, the castle is known from 987. In 1002, it was mentioned in the will of Roger I, Count of Carcassonne, who bequeathed the fortress to his youngest child, Bernard. In effect, the family ruling over the region were installed here which allowed them to control access to the upper Ariège valley and to keep surveillance from this strategic point over the lower land, protected behind impregnable walls.
In 1034, the castle became capital of the County of Foix and played a decisive role in medieval military history. During the two following centuries, the castle was home to Counts with shining personalities who became the soul of the Occitan resistance during the crusade against the Albigensians.