Rocca Abbaziale, Medieval fortress in Subiaco, Italy.

Rocca Abbaziale, also called Rocca dei Borgia, is a castle-abbey above Subiaco made of three buildings from different eras. The oldest is the 11th-century core with the large clock by Giuseppe Ravaglia, added under Pius VI; the east quadrangular bastion was built by Cardinal Rodrigo Borgia in the second half of the 15th century, and the late-18th-century palace by Pietro Camporese joins the two, with a double staircase and the Braschi coat of arms over the portal.

The fortress was built in the Middle Ages to protect the nearby monastery and was thoroughly rebuilt in 1476 under Cardinal Rodrigo Borgia. That renovation changed its appearance for good and turned it into one of the strongest fortified structures in the area.

The name Rocca dei Borgia comes from Cardinal Rodrigo Borgia, who restored the castle in 1476 and built the east-facing square bastion. In the 1550s the Colonna family had the first floor of that bastion frescoed with grotesques, attributed to artists around Perin del Vaga; the three rooms form the so-called Colonna apartment.

Access is by footbridge or steep stairs, so sturdy shoes make the visit easier. The site covers several levels, so it is worth setting aside enough time to walk through both the outer defensive areas and the museum rooms inside.

The east-facing square bastion was added by Cardinal Rodrigo Borgia in the second half of the 15th century; sources hold that his children Giovanni, Cesare and Lucrezia were born there to his mistress Vannozza Cattanei. A few decades later the commendatory abbot Francesco Colonna had its interior reworked into reception rooms.