Chenal Castle was built probably in the 13th century and had a rectangular floor plan. It belonged to the lords of Montjovet and only later became property of the Challant family, following the marriage between Ebalo the Great and Alexie of Chenal: in this way the two houses could control the passages along the road between Chenal and the Montjovet castle. The castle is nowdays in ruins.
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.