Castel Sant’Angelo
Mar 22, 2021

Castel Sant’Angelo

The Tomb that became a Fortress – Castel Sant’Angelo

The Castel St Angelo is one of the few monuments in Rome that has witnessed the passing of almost 2000 years.   Its look and function have changed many times with the fate of the city.  This huge round mound on the side of the river known as the ‘Mole Adriana’ has seen emperors, popes and invaders come and go.  It has changed use so many times in those years; from a mausoleum to a fortified stronghold. It became a protective fortress for the Vatican and a secret escape room for the popes in times of danger.  Later, it would become a prison and the fortress of Rome.  Popes have lived there, illustrious prisoners like Giordano Bruno and Beatrice Cenci were kept in the dungeons and the military might of Rome protected the city from the Castel’s ramparts.  What a history this one building has seen!  

Built by an Emperor

The huge round structure that makes up the base of the Castel Sant’ Angelo dates back to the height of the empire and one of the most famous Emperors, Hadrian.  He took Augustus’ Mausoleum (near Piazza del Popolo) as a model when he commissioned his grand tomb which took five years to build and was completed in 139CE. Originally the mausoleum had a huge square base with a cylinder on top, both were covered in marble.  Trees were planted on top of the cylinder and the whole thing was crowned with a golden quadriga or four horse chariot.  Hadrian also built the Pons Aelius, the bridge that leads to the mausoleum – it still provides a scenic approach from the centre of Rome and the left bank of the Tiber.

The Mausoleum housed the remains of a succession of emperors and their family until Caracalla in 212AD.   The imperial urns are long since gone - scattered by Visigoth looters and the bronze decoration and statues that once adorned Hadrian’s tomb were used as missiles and thrown at the Goths when they attacked Rome.

Mausoleum to fortress

The Mole Adriana (Hadrian’s mound) as it was known has always played an important role for Rome. Its proximity to St. Peter's Basilica, meant as Christian Rome developed, it became the stronghold of Christianity and its strategic location made it an indispensable outpost for anyone who hoped to control the city.   

The mausoleum was fortified early on by the emperor Aurelian, who built the defensive walls surrounding the ancient city.  He enclosed the castle in a system of walls, the Mausoleum complex and the river, would block invaders coming from the North; as in 547 CE when the Goths of Totila were successfully kept out.

The name of the castle today dates back to 590CE when Rome was devastated by plague.  According to legend the pope Gregory the Great saw the Archangel Michael atop the mausoleum, sheathing his sword. This was declared as a sign that the plague would come to an end and also signalled the castle’s importance to the church.  By the 9th century, the Mole Adriana was known as Castellum Sancti Angeli ‘Castle of the Angels’.  Pope Leo IV, (847-855) extended the area from the Mole to the Basilica of Saint Peter and it became a fortified citadel, known as Civitas Leonina.  Over the course of the Middle Ages the Castle was fought over by the various noble families who controlled the city.

Papal Residence

The powerful Orsini family controlled the castle for the whole of the 13th century, pope Nicholas III (Orsini) was the first to use it as his residence, of course he made major improvements. The Castle was now the definitive stronghold of the papacy.   At the same time the Passetto di Borgo was built - a huge walled passage complete with arrow slits that connected the Castle and the Vatican apartments.  Now the pope could escape the Vatican and wall himself up in the castle if need be.

It was in the 15th Century that the Castel would be extended to its full impregnable form, complete with two separate papal apartments, enough storage in the cisterns, grain silos and oil tanks to last out a lengthy siege and the outer wall was extended and four bastions added.  The cherry on top of the cake was the bronze statue of St Michael. 

A number of different popes would rebuild using the finest artists of the day, ultimately creating a finely decorated, massively stocked, fortified panic room.  Which is exactly what it became for the pope Alexander VI when he was under attack by the French in 1494 or Clement VII during the horrific sack of Rome in 1527 by the protestant, mutineer army of Charles V known as Landsknechts.  The pope left his apartments and ran along the 800 metre-corridor of the passetto to what would become his prison for almost a year.  Although you may not have heard of the sack of Rome, this event would forever shatter the church in two, protestant and catholic.


Clement VII was barricaded in for protection, but the darker side of the castle is surely its use as a prison through the ages.  The castle was first used as a gaol in 928 when a noblewoman called Marozia imprisoned the Pope John X, then had him strangled.  But it was much later in the 1490s that the infamous Borgia pope Alexander VI created prison cells on the lower floor of the Cortile del Pozzo reserved for important figures. The prisons had many illustrious guests, political prisoners or personal enemies of the pope.   Benvenuto Cellini, the goldsmith and sculptor from Florence (famous for Perseus and the head of Medusa) was held here for a year. His flamboyant escape is famous, while the pope entertained guests at the castle, the artist lowered himself from the top of the surrounding wall with knotted sheets, only to be caught and sent back.  Cellini was eventually pardoned thanks to influential friends, but most who were held at Castel St Angelo died.

There are eleven prisons on the so-called Giretto di Pio IV which were used for political prisoners and in the loggia of the papal apartment of Paul III is the Cagliostro, so called because in 1789 the famous adventurer Giuseppe Balsamo, the Count of Cagliostro, was held prisoner there. This was a luxury prison intended for prominent inmates.  

There are prison cells on different levels, but the most feared was a cell called Sammalò or San Marocco, named after a drawing from a former prisoner.  It was a small tight hole in which there was neither space to kneel, nor stand upright.  The condemned man was lowered into it from above and if he spent too long in there, became crippled.

Visiting the Castle

Today, the Castle is open to visitors and is well worth a visit - it is one of the few places you can trace the tumultuous history of the city.  There are seven levels to explore from the papal apartments at the top with rich frescoes down to the belly button of the monument - the Emperor’s tomb.  The views from the top of the castle are stunning and from the restaurant/bar.   In September, the Castle is open in the evenings with free guided tours.