The Friedberg castle was subsequently built to serve as a border security and customs post for the Duchy of Bavaria and Swabia, but put the town in opposition to the free city of Augsburg. It was built between 1257-1264 by Duke Ludwig II.
The castle was the cause of the first burning of Friedberg by Augsburg in 1396. The town was subject to the many frequent wars between Swabia, Bavaria and Augsburg.
A revival in the town's fortunes came when, in 1568, the Duchess Christine chose Friedberg castle as her seat following her husband's death. The town became the centre of Bavarian court life, but was short lived when the town was ravaged by the plague in 1599. More suffering came as the town was sacked twice by the Swedes during the Thirty Years War. After the war only the town hall, castle and city walls were left standing.
The castle is situated on a spur of and has an unusually deep moat. Since the renovation in 1982, Friedberg castle has been a museum.
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.