Llantilio Crossenny was a manor of the Bishops of Llandaff in the Middle Ages, and the site of their manor house can still be seen at Hen Gwrt. Their episcopal presence and the proximity of White Castle account for the 'exceptional scale' of the church. It is of Old Red Sandstone with a shingled spire. The tower and the nave are of the thirteenth century whilst the chancel was rebuilt in the fourteenth. The spire was added in the early eighteenth century and the whole was restored by John Prichard and John Pollard Seddon in 1856–7.
Either side of the East window of the chapel are two stone corbels which are said to represent Edward II. The interior also has a number of seventeenth and eighteenth century funerary monuments of high quality and stained glass by Charles Eamer Kempe.
References: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.