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 Basilica of Santa Maria in Trastevere is one of the oldest churches of Rome. The basic floor plan and wall structure of the church date back to the 340s, and much of the structure to 1140-43. The first sanctuary was built in 221 and 227 by Pope Callixtus I and later completed by Pope Julius I.
The inscription on the episcopal throne states that this is the first church in Rome dedicated to Mary, mother of Jesus, although some claim that privilege belongs to the Basilica di Santa Maria Maggiore. A Christian house-church was founded here about 220 by Pope Saint Callixtus I (217-222) on the site of the Taberna meritoria, a refuge for retired soldiers. The area was made available for Christian use by Emperor Alexander Severus when he settled a dispute between the Christians and tavern-keepers.
The church underwent two restorations in the fifth and eighth centuries and in 1140-43 it was re-erected on its old foundations under Pope Innocent II.