Mentioned from 1183, of the main castle are conserved the inner part of the walls, the barrel vaulted cistern and some spaces.
Built in a strategic position on a hill between Isera and Ravazzone, Pradaglia Castle is mentioned from 1183, when it was purchased in part by Trento bishop Salomone.
Since the beginning of the XIIIth century the castle, which had functions of control and refuge for the inhabitants of the bordering areas, was bound to the the village of Sacco and to the duty that was collected in it, undeniable source for the Trentino episcopacy.
In 1416 the fortress was ceded from Aldrighetto di Castelbarco to the duke Federico of Austria, count of Tyrol, in exchange for Nomi castle. Due to the precarious political situation of Lagarina valley the castle went back in possession of the Castelbarcos and a few years later the bishop Alessandro of Mazovia put an episcopal leader as keeper.
In the end of the XVth century the castle was already in ruins, but it still was granted as land possession until the suppression of the feuds in the XIXth century.
Of the original structure, now in ruins but recently restored, are conserved a portion of the inner walls, the barrel vaulted cistern and some spaces.