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The altar in the lower chamber, Mamertine prison  Rome, Italy

The Infamous Mamertine Prison and the Supposed Incarceration of Saint Peter

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The Mamertine Prison (a.k.a Carcere Mamertino in Italian) is an ancient prison located in Rome at the foot of Capitoline Hill overlooking the ruins of the Roman forum.  When it was built, this was Rome’s only prison  - and not a prison like we understand them today.  It was more like a dungeon where important state prisoners were lowered into, often prior to their execution. Consisting of two underground cells, it once held a room under the city sewers in the lower chamber. Historical sources have described it as dank and foreboding and inmates rarely stayed here for long periods of time.  Today, a sign on the exterior of the building proclaims it was the prison site of Saints Peter and Paul as it is believed the apostles were both incarcerated here prior to their crucifixion.

A Short History of Mamertine and its Famous Prisoners

Although its name is medieval, the Mamertine Prison is mentioned by several ancient writers, including Roman historian Titus Livius Patavinus (Livy), who dates its construction to the 7th century BC.  It was Ancus Marcius, the fourth king of Rome, who constructed this subterranean structure during his reign from 640-616 BC. 

The Romans were among the first to use prisons for criminal punishment and their jails were subterranean cells used for holding political prisoners and criminals for short periods of time, often in cramped, miserable conditions.  The practice of confining prisoners for extended periods of time as a form of punishment did not actually become widespread until the 15th century AD.

Prisoners were held in Mamertine to await execution or were simply allowed to starve to death out of sight. Rome's vanquished enemies were imprisoned and often died here.  Among the famous figures in history who spent their last days here include Vercingetorix, leader of the Gauls, who tried to rally the Gallic tribes into union against Caesar in 52 BC; Simon Bar Jioras, the defender of Jerusalem, who was defeated by Titus in 70 AD, and supposedly, the Apostles Peter and Paul.

Busts of Saints Peter and Paul, Mamertine prison, Rome, Italy

Busts of Saints Peter and Paul, Mamertine prison, Rome, Italy (Dennis Jarvis/Flickr)

The Architecture of Mamertine Prison

Between 600 and 500 BC, Mamertine was constructed as a cistern for a spring in the floor. Once the site was converted into a jail, two cells were created one on top of the other. 

Modern steps now lead down to the upper level of the prison which is at the original ground level of ancient Rome and thought to date back to the 2nd century BC.  The upper room of the prison is trapezoidal in shape, the walls are made of blocks of tufa, and there is a plaque on the right side naming some of the more famous prisoners and listing how and when each one died.  A second plaque names the martyrs and saints who were held here along with the names of their persecutors.  In the back is an altar with the busts of Saints Peter and Paul.

Plaque naming Famous Prisoners and their Executions, Mamertine prison, Rome, Italy

Plaque naming Famous Prisoners and their Executions, Mamertine prison, Rome, Italy (Wikimedia Commons)

The circular, lower room of the jail, known as the Tullianum, is named after its builder, Servius Tullius, from the 6th century BC.  This “dungeon” was located within a sewer system below the city and could only be reached by being lowered through a hole in the floor, now covered by a metal gate.  At the top, there is a stone said to have the imprint of St. Peter's head from when he was hurled down into the room.  The Tullianum was the most inner and secret part of the complex and served not as a place of punishment or torture but of detention and execution for condemned criminals.  The ancient historian Sallust said it was twelve feet underground and described its appearance as: “ disgusting and vile by reason of the filth, the darkness and the stench.” 

It was in this room, measuring 6.5 feet (2 meters)  high, 30 feet (9 meters) long and 22 feet (6.7 meters) wide, that prisoners who had been condemned to die, either by strangulation or starvation, awaited their fate.  An iron door at the end of the chamber opened to the Cloaca Maxima (the city’s main sewer), where dead bodies are said to have been dumped into the Tiber River. 

Saint Peter in the Mamertine Prison

There is a small altar in the lower chamber backed with a relief of Saint Peter baptizing his fellow prisoners.  On the front of the alter, standing out against a red marble background is an inverted cross, symbolizing the fact that St Peter was crucified upside-down in 64 AD.  A round opening in the floor, next to the altar, provides access to a spring which has existed in the floor since Classical times: this water is said to have healing properties which Saint Peter supposedly caused to miraculously rise up out of the ground to baptize fellow prisoners and guards with. 

According to early church tradition, Saints Peter and Paul were incarcerated in the Mamertine jail by the Emperor Nero prior to their execution.  It is thought to be this prison that St Paul makes reference to in the Bible (Timothy 4:21), when he urged Timothy to come visit him as he did not expect to get out until the following winter.  St. Paul also mentions imprisonment in other letters, such as in Philippians 1:13: " It has become known throughout the whole praetorian guard and to all the rest that my imprisonment is for Christ.”

The Liberation of Saint Peter from prison (1640), Antonio de Bellis

The Liberation of Saint Peter from prison (1640), Antonio de Bellis (Wikimedia Commons)

The Prison/Church of Today

In recent years, Italian archaeologists have discovered evidence to support the theory that St Peter was imprisoned in such an underground dungeon not long before his crucifixion.  Frescoes have also been found at the site associated with St Peter from as early as the 7th century. 

Mamertine prison was eventually converted into a focus of cult-like worship of St Peter by the 7th century, and by the 8th, was being used as a church. The site has been a place of Christian worship since medieval times and over the centuries, has taken on a great deal of Christian significance - which is ironic since a number of Christians were imprisoned here. 

Mamertine Prison today, Rome, Italy

Mamertine Prison today, Rome, Italy (Wikimedia Commons)

In the 16th century, a church, St Joseph of the Carpenters (San Giuseppe dei Falegnami), was built over the prison which still stands today attracting Christian pilgrims from around the world.

Featured Image: The altar in the lower chamber, Mamertine prison  Rome, Italy (Wikimedia Commons)

By Bryan Hill


"Mamertine Prison - Rome." Mamertine Prison - Rome.

"Sacred Destinations." Mamertine Prison.

Rome, Nick. "Archeologists Find Evidence of St Peter's Prison." The Telegraph. June 25, 2010.

"Mamertine Prison." Atlas Obscura.

"Roman Prisons." Roman Prisons.



Peter was never put in a headship over or greater tha any of the other Apostles. This is a fabrication that the West used to claim that the Patriarch of Rome was the "head of the church". All apostles, and then their descendants, the bishops, were all equal to one another. This was the way from the formation of the earliy Church. To this day the Orthodox Churches over the world operate like this, despite Constantinople's claim to be the "first among equals". And until Rome discards this papal magisterium, infallibility , and the claim to being the head of the church, reunion between East and West will never be posssible.

actually a goooooood website

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Bryan graduated with a Bachelor of Art in History from Suffolk University and has a background in museum volunteering and as well as working with children’s groups at the Museum of Science and the National Park Service.  He has traveled... Read More

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