The monastery at Kildonan was founded by a missionary St. Donnan, possibly from either Dal Riata or an Irish Kingdom. He and his monks were massacred in 617 by the local Pictish queen. In medieval times the island was held by Clan Donald. The church which currently houses the alleged sheela sculpture is thought to be a 16th century construction but there is evidence of earlier religious settlement in four cross slabs which date from the early medieval period. Records also list a religous settlement here in 725 so it would seem that the monastery continued after St Donan’s death.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.