There have been settlements on the site of Châtel-Argent castle since prehistoric times and through the Roman Era. There is a chapel dedicated to Saint Columba of Sens which was built sometime between 1050 and 1070. The castle first appears in a document in 1176 as Castrum Argenteum. The castle was improved around 1275 under the direction of Count Peter II's architect James St. George and castle grew to the configuration we see today. This castle had always been owned by the counts and the dukes of Savoy.
The ruins can be accessed from Villaneuve by walking The Rampa, a staircase carved into the rock of the valley wall. The castle is located in the town of Villeneuve in the Aosta Valley region, at about 10 km west of the city of Aosta. The most prominent feature left in the ruins is its watchtower keep measuring just under 10 meters in diameter which overlooks the town below. The ruins themselves cover about 6,300 square meters. When the castle was whole, it was estimated to be able to hold 700 people in times of danger.
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.