Excavations on Eilean na Comhairle in 1993 uncovered massive lime mortared walls, thought to be the remains of a mediaeval castle, On the basis of pottery found there, it is thought that this building may have been a hall-house built in the 13th century, Building ‘a’ shown on the plan, and overlying it, may have been the meeting place for the Council of the Isles, said to have sat here in the mediaeval period, as archaeological evidence shows it was occupied in the 15th century.
The walls of the castle were founded on rubble, retained around at least the south and west sides of the island by a thick dry-stone wall, evidently the remains of a dun or broch which forms the main mass of the island, This could have been a very significant structure in the Iron Age, An axe head dating from the Stone Age was found here so it would seem that Eilean na Comhairle, a man-made island, had been occupied for 5000 years.
Limited excavation to date has shown that the Council Island is mostly artificial, an accummulation of ruined buildings from different eras.
Above is pictured the remains of the Dun, superceded by the castle with the Council Chamber (a) and other buildings (b,c) on the surface.
Much of the bulk of the island may consist of the collapsed remains of an Iron Age fort – a broch or a dun. Some of its walls have already been traced, and the walls of the medieval castle seem to be founded directly on its stonework.
A fort of this type would have been the home of an important chief. The discovery of a polished stone axe in the 1994 excavations suggests that there may be yet earlier evidence of occupation on Eilean na Comhairle.
The Council Chamber
The foundations of three buildings now traceable on the surface of the Council Island appear to belong to the 15th century. The largest one, at the back of the island, may be the actual hall or chamber where the Council of the Isles met, with next to it a private residence for the Lords themselves.
In the 13th century a castle, with thick masonry walls held together with lime mortar, was built on the island. It was probably destroyed, systematically dismantled, in the 14th Century, perhaps in the Wars of Independence when the support of Robert Bruce by Angus Og made the MacDonalds unpopular with other factions in the country.