The origins of the castle date back to the 10th century.  In 1014, Alberico di Monterone had the property confiscated for supporting Arduino d'Ivrea.
In 1198 it passed to the Bulgaro family, in whose hands the manor remained until 1406. On the night between 4 and 5 May of that year the Captain of Fortune Bando of Florence occupied the castle. To obtain possession, Amedeo VIII of Savoy was forced to a siege that lasted until February 1409.
Subsequently the castle was divided and sold to 14 Biellese nobles. The following years, the Frichignono di Cecina brothers acquired ever greater shares of the castle and the territory of Castellengo. In 1630 Prospero was invested with the title of Count by Carlo Emanuele I; the noble coat of arms of the Frichignono is still visible today on the right side of the sundial of the castle. At the end of the 17th century, political and military conditions changed, and the transformation of the castle from a fortress to a noble residence began.
This transformation continued throughout the 1700s, drawing inspiration from French models. The Frichignono family died out in 1883 and the castle underwent a gradual abandonment, changing ownership several times. In 1990 the current owners began a careful conservative restoration, which is still in progress.
Guided tours upon reservation.

Location: Cossato (Baraggia and Plain)