Coeffin Castle was built on the site of a Viking fortress. The name Coeffin is thought to come from Caifen who was a Viking prince, and whose sister supposedly haunted the castle until her remains were taken back to be buried beside her lover in Norway.
Coeffin Castle was built in the 13th century, probably by the MacDougalls of Lorn. Lismore was an important site within their lordship, being the location of St. Moluag's Cathedral, seat of the Bishop of Argyll. The first written evidence of the castle occurs in 1469–70, when it was granted to Sir Colin Campbell of Glenorchy by Colin Campbell, 1st Earl of Argyll. It is unlikely to have been occupied in post-mediaeval times.
The ruins comprise an oblong hall-house and an irregularly shaped bailey. The great hall is an irregular rectangle, measuring 20.3 by 10.4 metres. The walls are from 2.1 to 2.4 metres thick. The bailey was mostly built at a later date than the hall. An external stair probably linked the entrance, in the north-east wall, to the bailey. A second door gave access to the sea to the south-west.
References:Saint-Georges de Boscherville Abbey is a former Benedictine abbey. It was founded in about 1113 by Guillaume de Tancarville on the site of an earlier establishment of secular canons and settled by monks from the Abbey of Saint-Evroul. The abbey church made of Caumont stone was erected from 1113 to 1140. The Norman builders aimed to have very well-lit naves and they did this by means of tall, large windows, initially made possible by a wooden ceiling, which prevented uplift, although this was replaced by a Gothic vault in the 13th century. The chapter room was built after the abbey church and dates from the last quarter of the 12th century.
The arrival of the Maurist monks in 1659, after the disasters of the Wars of Religion, helped to get the abbey back on a firmer spiritual, architectural and economic footing. They erected a large monastic building one wing of which fitted tightly around the chapter house (which was otherwise left as it was).