The remains of the Castle can be visited
Friberg Castle (Ruin) (Siat)

The Friberg ruin, a former hilltop castle, stands on a rocky spur above the village of Siat in Graubünden, Switzerland. It was once the center of a dominion in the Vorderrheintal.
History+
Friberg Castle was the ancestral seat of the noble lords of Friberg, who resided in the Vorderrheintal. Friedrich von Friberg is documented between 1255 and 1289 and fought against the Prince-Bishopric of Chur in 1255 alongside other Rhaetian nobles. Another lord was Rainger, who is mentioned as deceased in 1343. After the extinction of the Friberg family around 1330, the castle changed hands multiple times. At times, it was owned by Donat von Vaz and later by his daughter Ursula and her husband Rudolf von Werdenberg. Following a feud with the Rhäzünsers, the castle fell to them in 1343.
Source: Wikipedia · Licence: CC BY-SA 4.0
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 46.7917, 9.1617