The monument consists of Gylen Castle, a tower house probably completed in 1582, with a courtyard and outer defences, together with an area outwith the defences in which the remains of other - presumably related - buildings survive.
The castle occupies a high rocky ridge on a promontory, readily accessible only at its NE end. The tower, which has 4 storeys, is sited at a narrow isthmus near the SW extremity, and the NW and SE walls spring from the cliff edge. The basement is divided into a storage cellar and a pend which gives access through the castle to the entrance at the rear; both are barrel-vaulted. The upper storeys were not vaulted and each formed a single apartment with its own latrine closet. At the W angle of the tower is a jamb containing the entrance and a newel rising to the 3rd floor; above was a caphouse, reached by a corbelled stair turret in the NW wall; there is a bartizan at the N corner. Also at third-floor level, above the outer entrance to the pend, is an exceptionally fine combined box machicolation and oriel window.
The castle is stylistically related to a group of other castles built during the later 16th century in the west and north Highlands. These all contain mason-work suggesting that the masons who built them trained in west central Scotland. Despite a relatively short period of use, a blocked window in the stair jamb attests to structural alterations within the castle.
The end of the peninsula forms an inner court SW of the tower; there are marks of cultivation rigs and traces of a bank around the edge. Immediately NE of the tower is a forework comprising parallel gunlooped walls projecting from the corners of the tower. Beyond this is an outer court with traces of an enclosing wall (now a turf-covered bank). Within the court there are the stone footings of a sub-rectangular building and a rock-cut basin to collect rainwater. Footings of at least 2 further buildings and an enclosure lie outwith the defended perimeter and are included within the scheduled area.
The lands of Gylen were set in tack by Dougall MacDougall to his brother and heir, Duncan, in 1581. The castle was constructed by Duncan and a date-stone of 1582 suggests that Gylen was completed in that year (and implies that building commenced some time before 1581). The castle was attacked and burned by the Covenanting army in 1647, and marks of the fire are still visible on the masonry. Burnt beam ends still extant in some sockets support the local tradition that it was not re-occupied.
The area to be scheduled is irregular in shape and measures approximately 170m SW-NE by a maximum of 110m NW-SE. It contains the tower, the inner and outer courts, and an area immediately to the NE in which the remains of other structures exist, together with an area in which evidence relating to their construction and use may survive. The area is indicated in red on the accompanying map.
Statement of National Importance
The monument is of national importance as the remains of an exceptionally fine tower house with very high quality detail, the dates of whose construction and abandonment can be ascertained, together with the remains of an associated settlement. As the castle was burned, there is a strong likelihood of closely dateable artefactual remains. Study of the remains has the potential to enhance our understanding of the development of fortifications, the transmission of architectural influence within the more remote areas of Scotland, and social structure and relationships, and material culture, in early modern Scotland.