Mamertine Prison

The Mamertine Prison, known as Tullianum in ancient Roman times, is an ancient Roman prison built around the 8th century BC, making it older than the city of Rome itself. It is located in the Roman Forum (Comitium), on the northeastern slope of the Capitoline Hill, facing the Senate House (Curia) and the Imperial Fora of Nerva, Vespasian, and Augustus.

Ancient Rome did not typically imprison criminals for long periods; punishments usually consisted of fines, forced labor, or execution. Therefore, prisons were not places for long-term confinement but rather holding cells where prisoners awaited their sentence. Conditions were extremely harsh, with the prison being a dark, foul-smelling, and cold underground chamber. This prison typically held high-ranking captives. Defeated foreign generals, after being displayed in triumphal processions, would be imprisoned here and eventually publicly strangled, unless they happened to die naturally (Roman law did not recognize imprisonment itself as a form of punishment). In 63 BC, members of the Catilinarian conspiracy were held in this prison before their execution. Tradition holds that both Paul and Peter were imprisoned here before their martyrdom.

It’s unclear when this prison ceased operations, but the site has been used as a Christian place of worship since the Middle Ages. It is currently occupied by two churches: the upper level is the Church of Saint Joseph of the Carpenters (Chiesa di S. Giuseppe dei Falegnami), and the lower level is the Church of Saint Peter in Chains (S. Pietro in Carcere). The cross on the altar in the lower church is inverted because, according to tradition, Peter was crucified upside down.