Japelli collaborated with the engineer Bartolommeo Franceschini and the architect Giuseppe Petrelli, to whom we owe the merger of the balustrades of the terraces with the griffins. The painter Giovanni De Min, helped decorate the Greek room; Ippolito Caffi, the Roman room; Pietro Paoletti, the Pompeian room (or "Ercolana"); Vincenzo Gazzotto, painted the ceiling in the Renaissance Room.
Japelli worked with engineer Bartolommeo Franceschini and architect Giuseppe Petrelli to integrate the balustrades of the terraces into the griffins' design. The painter Giovanni De Min decorated the Greek room, Ippolito Caffi the Roman room, Pietro Paoletti the Pompeian room (or "Ercolana"), and Vincenzo Gazzotto painted the ceiling in the Renaissance Room.