prison
Happy, you would say, were the forbears of our great-grandfathers, happy the days of old which under Kings and Tribunes beheld Rome satisfied with a single gaol! Juvenal Satire III lines 312-3 translated by G. G. Ramsay
The one jail was traditionally supposed to have been built by Ancus Martius, the fourth king of Rome, with an underground dungeon added by Servius Tullius, the sixth king of Rome. It is here that Venus in Copper opens with Marcus Didius Falco having fallen victim to the wiles of his arch-enemy, Anacrites. Imprisonment of citizens does not seem to have been used as a punishment in Ancient Rome in Falco's day. The main function of the jail was as a place to keep state prisoners awaiting execution and people accused of crimes but unable to provide a surety to guarantee their appearance when their trial came up.
The Latin word for prison is carcer. The underground dungeon was called the Tullianum. This is the reason it was supposed to have been built by Servius Tullius, though it could also be derived from the word tullus, meaning a spring, some people thinking it was originally built as a reservoir. Varro, a Roman scholar of the first century BC, informs us that the Tullianum was also called the Lautumiae or quarries, either because there used to be a quarry nearby or after the quarries in Syracuse also used a place of detention. After our period, the building became known as the Mamertine Prison, which was and is revered as the place where Saint Peter was imprisoned in Rome.
For further information and links to the sources, see the entries for carcer in Smith's Dictionary of Greek and Roman Antiquities and Platner's Topographical Dictionary of Ancient Rome. LacusCurtius also has an an Italian translation for the entry carcer from Huelsen's Das Forum Romanum.
Some pictures of the Mamertine as it looks now and panoramic views of the lower and upper chambers.

The PhDiva has a post about imprisonment in Rome
Posted by: bingley | June 20, 2008 at 21:18
The first link isn't actually from Bill Thayer's LacusCurtius, but from James Grout's Encylopaedia Romana. They are both hosted by the University of Chicago.
Posted by: bingley | December 10, 2007 at 01:35
I just found this page from Bill Thayer's site, indicating that Sejanus was also strangled in the carcer before his body was thrown down the Gemonian Stairs. I found a confirmation in a JSTOR article The Consular Brothers of Sejanus, Freeman Adams, The American Journal of Philology, Vol. 76, No. 1 (1955), pp. 70-76 (limited access). Of course that would mean that his body was hauled up again after the strangulation. God, what a grisly conversation! ;-)
Here is a lurid description!
Posted by: IHahn | December 10, 2007 at 00:06
True, but they were not Roman citizens.
Posted by: IHahn | December 09, 2007 at 23:41
What about the prisoners who were paraded in the triumphs? Weren't at least some of them dispatched by strangulation in the Tullianum?
Posted by: bingley | December 09, 2007 at 01:08
I think the Catiline conspirators may have been an exception due to the hastiness of the proceedings. Usually, the punishment was permanent exsilium and aqua et igni interdictio, i.e., the loss of citizenship and thus of all legal protection. Originally, exile was voluntary to escape the death penalty, but it was institutionalized in the late republic. According to the OCD, the principate had two versions, deportatio and a milder one, relegatio.
And of course there was the truly grisly punishment for parricides.
Posted by: IHahn | December 09, 2007 at 00:19
I wonder how this actually worked. Were the executioners lowered down into the Tullianum with the prisoners and then pulled up again or did they have a separate entrance and the lowering down of the prisoner had some sort of symbolic significance of sending them down into the underworld?
Plenty of other grisly ways for senators to die, as the proscriptions showed.
Posted by: bingleyausten | December 08, 2007 at 22:26
The Tullian dungeon was described by Sallust (Conspiracy of Catiline): "sunk about twelve feet underground.... its appearance is disgusting and horrible, by reason of the filth, darkness, and stench."
The Catiline conspirators had to be lowered into it, and then were strangled. Not a nice way for patricians to die. I wonder if that was unusual, given their rank.
Posted by: judith weingarten | December 02, 2007 at 11:27