The cardinal was also the owner of a large part of the area which extended, behind the palazzo, above the ruins of the imperial fora of Trajan and Augustus, known by the name "Pantano" due to being subject to impaludamenti or flooding.

At the start of the 18th century, the palazzo was leased to several prominent personalities, including marchese Francesco Maria Ruspoli from 1705 to 1713, who made it the site for a private theatre and hosted illustrious musicians of the time such as Handel, Alessandro Scarlatti and Arcangelo Corelli.

The provincial deputation of Rome acquired the palazzo as their base in 1873, commissioning the architect Gabet to complete the right side on via de’ Fornari, at the top of vicolo di San Bernardo.

The Palazzo's art treasures include the statue of Ulysses by Ugo Attardi, as well as works depicting "Aeneas and Anchises" and "Europa", made by Sandro Chia to commemorate the 135th anniversary of the provincial administration of Rome, now located at the entrance.

It is believed to be part of a nearby residential scheme found over 100 years ago prior to the 1907 construction of Palazzo delle Assicurazioni in Piazza Venezia.