Ortenburg castle in Bautzen stands on the site of 7th century fort enlarged by Henry I in the 10th century. In the 15th century the castles was rebuilt in the late-Gothic style by Matthias Corvin, King of Hungary, following two devastating fires. The tower on the north wing still bears a relief representing the king. In 1698, at the height of the Baroque period, three Renaissance gables were added to the castle.
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.