The history of the castle can be said to have begun around the year 1500 when Pietro Gromo, an important gentleman of Biella, bought from the Avogadro family of Valdengo the feud and with it a courtyard dating from around the year 1000.
The new owner of the feud added to this construction a fortified housev with a round tower presumably built for observation purposes and not defence: Ternengo has almost always been a tranquil and hard working place.
The castle then assumed a rather unusual feature for this area of a “Villa Castellata”.

Even today, not withstanding the modifications carried out in the course of the centuries which have changed its original aspect, it can be admired in all its beauty, because it has been well maintained.
One feature has remained unchanged with time: the atmosphere of peace and serenity which you perceive inside the walls has been faithfully kept, as it is described by the four inscriptions found on the vaulted ceiling of the staircase: “Opus, opes, studium, parcitas”..... which even now are here present....