Conrad I, Count of Vintimiglia, built the castle in Roquebrune-Cap-Martin in 970 to defend the Western border of his feudal domain from attack by hordes of Saracens that rampaged around the area. Initially the entire village was encompassed by the castle. The keep's military strength was reinforced in the 15th century by the Grimaldi family. In 1808 the castle was sold as a Bien National to five Roquebrune inhabitants. A century later, in 1911, it was sold again – this time to wealthy Englishman Sir William Ingram, who set about renovating it but eventually gave it to the town of Roquebrune in 1921. The castle overlooks the medieval village and its atmospheric alleyways, sometimes carved out of the rock itself.
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.