San Colombano Castle originates probably from the 6th century AD, but if was mentioned first time in the 10th century. The current castle was built by Frederick I, Holy Roman Emperor (Federico Barbarossa). During his second visit to Italy, he destroyed the existing castle, but decided to build a new one in 1164. The next reconstruction began in 1370. Later it has been conquered and rebuilt several times.
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.