The Mamertine Prison (), in antiquity the Tullianum, was a prison (carcer) with a dungeon (oubliette) located in the Comitium in ancient Rome. It is said to have been built in the 7th century BC and was situated on the northeastern slope of the Capitoline Hill, facing the Curia and the imperial fora of Nerva, Vespasian, and Augustus. Located between it and the Tabularium (record house) was a flight of stairs leading to the Arx of the Capitoline known as the Gemonian stairs. The church of San Giuseppe dei Falegnami now stands above the Mamertine. Name and origin The origins of the prison's names are uncertain. The traditional derivation of "Tullianum" is from the name of one of the Roman kings Tullus Hostilius or Servius Tullius (the latter is found in Livy, Varro, and also Sallust); there is an alternative theory that it is from the archaic Latin tullius "a jet of water", in reference to the cistern. The name "Mamertine" is medieval in origin, and may be a reference to a nearby temple of Mars. According to tradition, the prison was constructed around 640–616 BC, by Ancus Marcius. It was originally created as a cistern for a spring in the floor of the second lower level. Prisoners were lowered through an opening into the lower oubliette. Use Imprisonment was not a sentence under Roman statutory law, though detention is mentioned in the Twelve Tables and throughout the Digest. "Detention," however, includes debt bondage in the early Republic; the wearing of chains (vincula publica), mainly for slaves; and during the Imperial era a sentence of hard labor, was at the mills, mines or quarries. Slaves or lower-status citizens sentenced to hard labor were held in prison camps. Incarceration (publica custodia) in facilities such as the Tullianum was intended to be a temporary measure prior to trial or execution; abuses of this principle occurred but were officially censured. Located near the law courts, the Tullianum was used as a jail or holding cell for short periods before executions and as a site for executions. In 63 BC, certain co-conspirators of Catiline, including Publius Cornelius Lentulus Sura, were held briefly in the Tullianum and executed there for their alleged plot to overthrow the government. In this case, the executions were conducted hastily, without due process of appeal, during the consulship of Cicero, who was later exiled for his actions. Sejanus was held