Tradition holds that the cardinal was able to dissuade the mobs by pointing to the bust of Charles I of Spain, Holy Roman Emperor, on the facade, and invoking that king's restrained taxation.
[3] The base floors of the facade are constructed with rusticated piperno rock, carved with sturdy but tall Ionic pilasters.
The superior tympanum of the portal is flanked by two reclining statues, each with cornucopiae, depicting Magnanimity (with lion) and Charity (with eagle).
The superior floors also are rich in sculptural elements, with two stories of carved pilasters, the topmost of which are surmounted by symbols of the Firrao family: grapes, lions, and raring horses.
But the striking element are the seven medallion niches containing marble busts of rulers of Naples, mostly from the House of Habsburg, which Firrao served.