Inishmacsaint (meaning 'Island of the Sorrel Plain') is a monastery located on an island off the western shore of Lough Erne, Northern Ireland. The site includes the ruins of a monastic church and an early stone cross, probably from the tenth and twelfth centuries. Inishmacsaint was founded by St. Ninnidh, (d. 523/30). The original monastic buildings were probably damaged or destroyed during the raids of the ninth or tenth centuries.
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.