Mamertine Prison, Rome

The Mamertine Prison (a.k.a. Carcere Mamertino or San Pietro in Carcare) is an ancient prison at the foot of the Capitoline Hill in Rome.

The Mamertine Prison consists of two gloomy underground cells where Rome's vanquished enemies were imprisoned and usually died, of either starvation or strangulation. Famous prisoners here include the Goth Jugurtha, the indomitable Gaul Vercingetorix and, according to legend, St. Peter.

There is no archaeological evidence or early written account that Peter was here, but the legend had taken root by the 5th century and the prison attracted early pilgrims. It remains a pilgrimage site today and a church, San Giuseppe dei Falegnami, now stands over the prison.



The legend that Peter and Paul were imprisoned here has not been found to predate the 5th century, yet it is not impossible that it is based in fact.

Paul may have been detained here before he was executed at the Aquas Salvias (at the Abbazia delle Tre Fontane) and Peter before being executed in Nero's circus on Vatican Hill.

Paul mentions imprisonment several times in his 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."

According to later legend, St. Peter caused a spring to miraculously well up in the prison so that he could baptize his fellow prisoners. This spring is said to have miraculously cured the illnesses of pilgrims.

History of the Mamertine Prison

The Mamertime Prison is mentioned by several ancient writers, including Livy, who dated its construction to the 7th century BC under King Ancus:

The lower room of the remaining part is known as the Tullianum after its builder Servius Tullius (6th century BC). This part served as a place not of punishment but of detention and execution for condemned criminals. The ancient historian Sallust said it was 12 feet below the ground and "neglect, darkness and stench make it hideous and fearsome to behold."

The prison was in use until at least the late 4th century AD, when it was mentioned by the historian Ammianus Marcellinus. After the prison ceased to be used for its original purpose, it became a pilgrim site and accumulated various legends. It later became known as Mamertinus.

In the 16th century, the church of San Guiseppe dei Falegnami was built above the prison.

What to See at the Mamertine Prison

Modern steps lead down to the upper level of the prison, which is at the original ground level of ancient Rome. The doorway is modern.

The upper room of the prison is trapezoidal in shape and dates from the 2nd century BC. The walls are made of blocks of tufa and bears a plaque on the right naming the more famous prisoners, listing how and when each one died. A second plaque names the martyrs and saints who were held here with the names of their persecutors, and the notable visitors who came here on pilgrimage. In the back is an altar with the busts of Saints Peter and Paul.

The lower room was originally accessed through a round opening in the floor of the upper room, which is now covered with a grate. Today, access is by means of a modern staircase on the left. At the top, look for a stone said to have the imprint of St. Peter's head from when he was hurled down into the prison.

The lower room, the Tullianum, is circular and made of blocks of peperino held together without mortar. This was the most inner and secret part of the larger complex, and here the condemned were thrown and usually strangled.

Here there is a small altar, topped with a relief of St. Peter baptizing his fellow prisoners. The upside- down cross on the red marble front lends the desolate place an extra-sinister air, but that's the Cross of St. Peter, who was crucified upside down.

To the left of the altar is a column to which both Peter and Paul were tied and from there they converted their guards to Christianity.

A round opening in the floor next to the altar provides access to a spring which has surfaces in the floor since Classical times: this is the one that Peter is said to have miraculously created for baptism and which pilgrims have long believed to have healing properties.

Quick Facts on the Mamertine Prison

Site Information
Names:Carcere Mamertino · Mamertine Prison · San Guiseppe dei Falegnami · San Pietro in Carcare
Categories:churches; shrines; prisons
Dates:7th/6th C BCE
Status: active
Visitor and Contact Information
Coordinates:41.893192° N, 12.484557° E
Address:Foot of the Capitoline Hill
Rome, Italy
Hours:Daily 9-12:30 and 2-5
Lodging:View hotels near the Mamertine Prison
Note: This information was accurate when first published and we do our best to keep it updated, but details such as opening hours and prices can change without notice. To avoid disappointment, please check with the site directly before making a special trip.


  1. Personal visit (July 16, 2006).
  2. Matilda Webb, The Churches and Catacombs of Early Christian Rome: A Comprehensive Guide (Sussex Academic Press, 2001).
  3. Fodor's Rome.

More Information

Exterior of the ancient Mamertime Prison, with the 16th-century church of San Giuseppe dei Falegnami above. © Holly Hayes
A sign on the exterior proclaims the Mamertime the "prison of the Saints and Apostles Peter and Paul." © Holly Hayes
This plaque on the right wall of the upper level names some of the more famous prisoners of the Mamertime. © Holly Hayes
The modern but well-worn stairs to the lower room of the prison, where St. Peter and Paul are believed to have... © Holly Hayes
A small altar in the lower room of the Mamertime Prison. The upside-down cross lends the desolate place an... © Holly Hayes
The miraculous spring, believed to have healing properties. © Holly Hayes
Plaque in the lower room wall. © Holly Hayes
© Holly Hayes

Map of the Mamertine Prison, Rome

Below is a location map and aerial view of the Mamertine Prison. Using the buttons on the left (or the wheel on your mouse), you can zoom in for a closer look, or zoom out to get your bearings. To move around, click and drag the map with your mouse.