The construction of the palace began in 1576, when Sisto V’s sister, Camilla Peretti, purchased “four ground-level houses” to transform them into a cardinal’s residence and noble home for the Peretti family. It remained so until Sisto V’s death in 1590. Since 1790, it has been owned by the Massimauri family and, between 1900 and 1960, it housed the Carabinieri barracks on the second floor. The architecture, both exterior and interior, reflects the succession of restoration interventions: from the 16th-century masonry incorporated into the defensive walls, to the evocative underground spaces used as an oil mill in the second half of the 19th century, passing through the charming inner courtyard and the rooms with coffered ceilings on the noble floor.