Rocca Pia
Description
Built in part by reusing materials taken from the nearby Bleso amphitheater, Rocca Pia was commissioned by Pope Pius II Piccolomini (1405-1464), who began work in 1461.The site, close to the medieval urban wall, was chosen for strategic reasons, both for the military defense of the city, as an element of allocation of the papal troops, controlling all the access routes to Tivoli and the entire territory towards Rome, and to control the city and the internal contrasts between the Orsini and Colonna families.
The complex consists of four towers of different sizes, connected by high walls and enclosed by Guelph battlements: at various points, fire mouths open. The entrance to the fortress on the west side was protected by a deep defensive trench and a drawbridge.
In the 19th century, the fortress, used as papal barracks and prison, underwent structural modifications that changed the architectural appearance of the inner courtyard, in which a body was added leaning against the north wall, resulting in changes to the minor towers and greatly reducing the width of the courtyard.
In the 19th century it alternated the function of papal barracks with that of a prison, capable of housing up to 100 inmates in the circular towers; this function it maintained until 1960, thus remaining in existence to the present day, bearing witness to more than 500 years of history.