The palace, which houses the Civic Library, blends in with the various buildings that make up the large Santa Croce complex, a former Augustinian convent. When they acquired the building, the Counts of Langosco made important changes to the pre-existing situation. The most valuable part (two-flight grand staircase and entrance hall) was built in 1776 to a design by Giovanni Battista Borra. At the time of the Gonzaga family, the palace was the seat of the Casalese Senate and the large entrance hall, restored in the 1960s, is still referred to as the Salone del Senato