While the work for the expansion and architectural renovation of the residence was being carried out under the supervision of Carlo and Amedeo di Castellamonte, following the wish of Cristina of France, the decoration of the two first floor apartments on the Noble Residential Floor progressed. The apartments are identical both in number of rooms, both in their disposition, but different in decorative choice. The project wanted a sumptuous decoration using stucco-work and paintings accompanied by “corami” (leather works used like tapestries) on the walls. The works started with the central Great Salon and the apartment facing south, towards Moncalieri, formed by five rooms and a cabinet. The order is given to the family of plasterers and painters, coming from the Lake region, leaded by Isidoro Bianchi, who had already been regularly involved in other Savoy architectural projects such as Rivoli or the Ducal Palace. Bianchi works here assiduously with his sons Pompeo and Francesco between 1633 and 1642.
The main theme chosen for each room is represented by the fresco at the center of the ceiling, as the starting point, and then carried around to the stucco-work and frescos and even to the area just underneath the wall friezes. If the official apartment belonging to Cristina is strongly distinguished by the golden stucco-work and is the master piece of the Bianchi family, the rooms facing north, designated for the young prince Carlo Emanuele, are decorated at the beginning by the Bianchi, and later by other artists belonging to talented families coming from the Lake region, both painters and sculptors, such as the Casella and the Recchi (1633-1646).
The decoration of the apartments is well preserved, even if some rooms were re-decorated and modified during the eighteenth century; the general decorative programme and each episode were master-minded by Count Filippo di San Martino d’Aglié. The Count’s choice of style for the southern apartment rooms facing the Po was based on Ovidio’s poem.