Nyon Castle is first mentioned in 1272, but probably dates back to the Lords of Prangins. It was rebuilt by Ludwig I of Savoy. The rectangular building was built in a variety of building styles. In 1463, it was extensively rebuilt. Following the Swiss Confederation invasion of Vaud in 1530, the Bernese bailiff was at Nyon. In 1574-80 the castle was converted into the seat of the bailiff. It remained the seat of the bailiff and was renovated several times in the following centuries.
Today Nyon Castle is a museum.
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.