How the Roman Prison That Once Held Sts. Peter and Paul in Captivity Became a Holy Site

Discover the ancient prison reserved for important state prisoners awaiting their execution where, according to tradition, Sts. Peter and Paul were imprisoned before their martyrdom.

Top to bottom: Busts of St. Peter and St. Paul in the Carcer, the upper level of the Mamertine Prison
Top to bottom: Busts of St. Peter and St. Paul in the Carcer, the upper level of the Mamertine Prison (photo: EWTN News)

ROME — Hidden below the Church of St. Joseph of the Carpenters, among the ruins of ancient Rome, lies the city’s oldest maximum-security prison: the Mamertine prison.

Originally known as the Carcer Tullianum — possibly named after the Roman kings Tullius Hostilius or Servius Tullius — the Mamertine prison was, according to tradition, built by the legendary fourth king of Rome, Ancus Marcius, in the seventh century B.C.

Although it is believed that it was originally created as a cistern for a spring in the floor of the second lower level — indeed, the word tullius is also Latin for “a jet of water” — the site quickly became an integral part of the Roman justice system for centuries.

“This was an ancient Roman prison from the very foundation of the city of Rome,” Father John D’Orazio, an American priest based in Rome offering pilgrimages with Opera Romana Pellegrinaggi, told the Register.

Father John D’Orazio 2
Father John D’Orazio, an American priest based in Rome, speaks about the history of Mamertine Prison.(Photo: EWTN News)

The prison was built at the foot of the Capitoline Hill, near the Arx — Latin for “citadel” — which “comes from the Latin arcere, which means “to keep away,” Father D’Orazio explained. “So, there is kind of a play on words, between archere and carcere, which means ‘prison.’”

The location of the prison was strategic: Situated at the foot of the epicenter of the Roman Empire, in front of the Forum — the center of public life — it was a clear warning symbol of Rome’s unappeasable justice against its enemies.


A Prison for Important Persons

“It wasn’t a prison for petty thieves,” Father D’Orazio clarified. “It was a prison for the most important enemies of the state. They wanted people to see that these prisoners were being tortured and sentenced to death.”

Among the many historical figures condemned to death by starvation, strangulation or beheading in the Mamertine Prison, several deserve to be mentioned: Jugurtha, king of Numidia, and Gallic chieftain Vercingetorix, both publicly executed by strangulation in 104 B.C. and 46 B.C., respectively. Also, Pope Sixtus II and St. Lawrence are said to have been incarcerated there.

The prison consists of two superimposed floors: the upper level is known as the Carcer, while the lower level is the Tullianum

Tullianum, the lower level of Mamertine Prison
Father John D'Orazio looks at the Tullianum, the lower level of Mamertine Prison where Sts. Peter and Paul where allegedly held in captivity before their martyrdom. The plaque indicates where Sts. Peter and Paul were chained in the Tullianum.(Photo: EWTN News)

“There was no entrance or exit from the lower area,” Father D’Orazio explained, pointing to a hole in the ground of the Carcer. “There was only this hole right here in the ground where the prisoners would be thrown down” to be left to starve to death or to await their execution.

 Lower level of the Mamertine Prison.
Grill over the hole where prisoners where thrown down into the lower level of Mamertine Prison(Photo: EWTN News)


Historical Evidence of the Saints’ Imprisonment

According to tradition, the Mamertine is also the place where the apostles Peter and Paul were imprisoned.
It is believed that the Tullianum was where Sts. Peter and Paul were incarcerated until their respective martyrdoms, because of the seriousness of their “crime”: refusing to ascribe absolute power and divinity to Roman Emperor Nero.

It is probably this prison that Paul referred to in his Second Letter to Timothy, when he urged Timothy to visit him soon: “Do your best to come before winter” (2 Timothy 4:21).

Indeed, while it is believed that St. Paul wrote his letters to the Ephesians, Philippians and Colossians and to Philemon during his first Roman imprisonment during Nero’s reign (according to tradition, Paul was imprisoned in his own house under house arrest for two years during his first imprisonment) it is assumed that he wrote his Second Letter to Timothy during his second imprisonment in Rome, shortly before his martyrdom. For instance, St. Paul writes: “Do not be ashamed then of testifying to our Lord, nor of me his prisoner” (2 Timothy 1:8).

Apart from the writings of some early saints such as St. Peter of Alexandria, the main evidence that St. Peter was also imprisoned in the Tullianum, together with St. Paul, can be found in one of the earliest of the apocryphal acts of the apostles in Christianity, the “Acts of Peter,” dating to the late second century A.D. 

In addition, frescoes inside the prison and Roman historian Ammianus MarcellinusHistories (XXVIII, 1, 57) from the fourth century associate the site with the veneration of Peter and Paul from the earliest centuries after the death of Christ. 


‘Apostles Peter and Paul,’ by Andrei Nikolajewitsch Mironow CC BY-SA 4.0, via Wikimedia Commons


Miraculous Events in the Prison

“It is here that Sts. Peter and Paul would have been chained,” Father John said, pointing to a dark corner of the Tullianum.

To this day, the papal Basilica of St. Paul Outside the Walls houses the relics of St. Paul’s chains, and the Basilica of St. Peter in Chains houses those of St. Peter.

Despite the harsh conditions of the apostles’ incarceration, the apocryphal “Acts of Peter” “recounts miraculous events around their martyrdom, as signs of God’s blessings and mercy to them in this time of strife.”

“For example,” Father D’Orazio said, “Peter was able to give witness to the Gospel even here in the Mamertine Prison, to the very prison guards who were watching over him. He was able to tell them about the Gospel, and they listened to his words. They welcomed the message of the Gospel into their hearts and wanted to be baptized.” 

“But there was no water with which to baptize them,” Father John continued. “So Peter had water spring forth miraculously, and he used that water to baptize them. These prison guards, Processus and Martinian, themselves became martyrs of the Gospel.”

Mamertine Prison converts
Artwork depicting St. Peter baptizing the two warders Processus and Martinian(Photo: EWTN News)

Following their baptism, the two warders — who are today mentioned in the Roman Martyrology — were then arrested, tortured and beheaded by Nero’s order.

“Peter and Paul showed great courage,” Father D’Orazio emphasized. “They embraced the cross, and not only in an individual manner, but together. Peter and Paul, who had very different personalities, different approaches, different charisms, still had a great respect for one another and wound up sharing together the experience of martyrdom here in Rome.” 


Fresco, Sts. Peter and Paul - Mamertine Prison
Fresco from the first centuries A.D. depicts Sts. Peter and Paul on each side of Christ, indicating that the prison quickly became a place of Christian worship.(Photo: EWTN News)

Receiving Their Crowns of Glory

After their imprisonment, tradition holds that St. Peter was crucified upside down in Nero’s circus on the Vatican Hill — where the obelisk “The Witness” stands today.

St. Paul is said to have been decapitated just outside of Rome, at the Aquas Salvias, where his severed head allegedly rebounded three times, miraculously giving rise to a source of water each time that it touched the ground. This is how the place earned the name San Paolo alle Tre Fontane, meaning “St. Paul at the Three Fountains.”

Over time, the Mamertine Prison — which was in use until the fourth century — “became a place of Christian worship,” Father D’Orazio explained, “just as the Colosseum and other places of Christian martyrdom in Rome.”

Whether or not the Mamertine Prison was the actual place of Sts. Peter and Paul’s imprisonment, their lives and deaths are without a doubt a testimony to a persevering faith.

Reflecting on how “the Gospel always invites us to live according to truth” and how “living a Christian life means being able to stand up for what is true and just,” Father D’Orazio explained:

“The story of the martyrs is one of great courage and of being able to stand up for the truth, even if it means losing one’s life. The truth of the Gospel is indeed more precious than the gift of life itself, which is one of the most precious gifts that God has given us.”

“Martyrdom is also a gesture of great love,” Father D’Orazio continued, for it is an act “of giving one’s life for God and for one’s neighbor.”

“Right next to the Maritime Prison is the ‘Sacred Street,’” the priest added, “where the Roman emperors would enter Rome after winning a great battle to be crowned with a laurel wreath as a sign of their triumph.” 

“The same is applied to the martyrs as we can see here,” Father D’Orazio said, pointing to a fresco depicting Sts. Peter and Paul inside the Carcer. “Also, Peter and Paul received their crowns of glory after having given their lives for the Gospel.”