Egerberk is a ruined castle near Klášterec nad Ohří. First mentioned in 1317, the castle belonged to Wilhelm who first started to bear the attribute name 'of Egerberg'. Wilhelm was a friend of John of Luxembourg and accompanied him on his journeys. His brother Fritz was given several villages and started to bear the name of one of them - Pětipsy. The castle was then sold to the House of Šumburk from a nearby castle. In 1384 Egerberk was added to the property of the House of Škopek and Jindřich Škopek z Dubé started a large-scale reconstruction. At the end of the 16th century the castle was already abandoned.
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.