Castle Roy is one of the oldest castles of its type in Scotland unique in that it is largely unaltered, whilst most other castles have been extensively modified over the centuries. The castle is thought to have been built at some point in the early 13th century, replacing an earlier wooden motte and bailey keep of Norman influenced design. In accordance with its early design it is one of Scotland’s simplest forts consisting of four curtain walls, about 7 ft. thick, forming a square. Presumably the walls defended a number of timber buildings which have since disappeared. One theory is that Castle Roy was built by James, son of the Earl of Mar, in 1226, after having receiving the title of Lord of Abernethy from King Alexander II. It may have become a residence of the powerful Comyn family, rivals of the famed King Robert the Bruce.
In 1548 the Castle was named in the Charter of the Earldom of Moray and therefore possibly it was still in use, although in the era of gunpowder will only have been of use as a fortified shelter.
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.