During the 6th century AD a small community of monks settled on the Inishkeel island. Their religious leader was Saint Conall Cael, from whom the island later derived its name. During the following centuries Inishkeel was a traditional destination of pilgrimages. Remains of the church and the connected buildings as well as some carved stones can be seen on the island. For its artistical and archeological importance the island was declared National Monument. A bell known as St Conall Cael's Bell remained on Inishkeel up to the 19th century and was then acquired by the British Museum.
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.