Built around 1250 by the lords of Berkule, Calenberg Castle was granted to the Papenheim family in 1307 and later became known as Rave von Calenberg. After a feud over inheritance in 1464, it was resolved in 1471. In 1868, Hugo Schuchard purchased the estate, including the castle, and extensively renovated it from 1880 to 1884. The castle served various purposes over the years, including housing refugees after 1945. In 1972, it was acquired by Karl-Heinz Rehkopf and faithfully restored.
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.