Although Siersberg Castle was first mentioned in 1178, it was probably already built in the 11th century. It was built atop an almost 300-meter-high mountain overlooking the valleys of the rivers Saar and Nied.
During the Thirty Years' War, in 1634, the castle was taken by French troops. In the next decades it was taken and retaken several times by both parties, which of course caused damage to the castle. In 1670 the French again occupied Lorraine. When they retreated again in 1677 they partly blew up the, by then already dilapidated, castle. After that, Sierberg increasingly lost its military importance and its decay progressed.
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.