Wartenstein castle was built around 1206 by Konrad von Zwiefalten. The castle is mentioned for the first time in 1208 and later owned for several families. In 1341 it was rebuilt and repaired by abbot Hermann II of Arbon. After the middle of the 16th century sources describe the castle dilapidated. The Abbey Pfäfers gave in 1586 the worthless site to the local residents as a quarry.
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.