Schloss Leonberg was founded in 1248 by count Ulrich I of Württemberg. The original castle was modified between 1560 and 1565 by the master builder Aberlin Tretsch by order of the duke Christoph. The widow of Frederick I of Württemberg, Duchess Sibylla (1564-1614), used the castle from 1609 as a widow's residence. Later, the castle was still repeatedly used as a residence. The castle today is a tax office.
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.