Of the rectangular buildings with free-standing keep, built in the 12th century, only the remains of the east and south wings of what used to be an important castle are preserved. The alterations carried out in the 18th century, following diverse war damage, resulted in the palatial building as it can be seen today. During the Second World War the castle was seriously damaged, but was reconstructed in 1952. This construction work was carried out in a simple reduced form; only on the valley side does the castle resemble its former image. Schleiden castle today is merely the remains of what used to be a much more extensive castle complex of several buildings.
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.