The possibly 15th century or 16th century domestic establishment ruins on St Margaret's Island may have been constructed using materials from an early church on the site.

Set on the northern edge of a cliff-girt islet, whose summit area is roughly 100m east-west by 33m, part of St Margaret's Island are ranges of ruinous stone buildings, that have displayed some medieval architectural detail, and are laid out about a court, open to the sea, about 18.8m north-west to south-east by 18.3m. Thought to have been a cell of Caldy Priory (Nprn245), the buildings were divided into quarrymen's cottages in the 19th century; the largest building, an 18.3m by 5.8m north-east to south-west range, is suggested to have been a chapel. Further details of the buildings are depicted on OS County series mapping (Pembroke. XLIV.3 1888). Other features may be identified from aerial photographs: on the islet, a north-east to south-west rectangular structure to the south of the ruins, and possible terraces along the cliff-top to the east.

J.Wiles 17.01.05