The uppermost vault is still below the level of the surrounding soil, and the entrance to it is by the church of San Giuseppe di Falegnami, the patron of the Roman joiners, built over it. Beneath is a subterranean chapel, forming a sort of crypt to the upper church, called San Pietro in Carcere, containing a curious ancient crucifix, an object of great veneration, and hung round with blazing lamps and rusty daggers, pistols, and other deadly instruments, the votive offerings of bandits and assassins who sought at this shrine of the chief of the apostles to make their peace with heaven. Descending from the chapel by a flight of steps we come through a modern door, opened through the wall for the convenience of the pilgrims who annually visit the sacred spot in crowds, to the ancient vestibule, or grand chamber of the prison, commonly called the Prison of St. Peter from the church tradition which asserts that the great apostle was confined here by order of Nero before his martyrdom. The pillar to which he was bound is still pointed out in the cell; and Dr. Parker, lifting up its cover, showed us a well in the pavement of the floor, which is said to have sprung up miraculously to furnish water for the baptism of the jailors Processus and Martinianus whom he had converted, though, unfortunately for this tradition, the fountain is described by Plutarch as existing in the time of Jugurtha's imprisonment. Indeed there is every reason to believe that this chamber was originally a well-house or a subterranean cistern for collecting water at the foot of the Capitol, from which circumstance it derived its name of Tullianum, from tullius, the old Etruscan word for spring, and not from Servius Tullius, who was erroneously supposed to have built it. The whole chamber in primitive times was filled with water, and the hole in the roof was used for drawing it out. Dr. Parker gave us a little of the water in a goblet, but, notwithstanding its sacred reputation, it tasted very much like ordinary water, being very cool and fresh, with a slight medicinal taste. He also pointed our attention to a rugged hollow in the wall of the staircase, and told us that this was the print of St. Peter's head in the hard stone, said to have been produced as he stumbled and fell against it, coming down the stair a chained prisoner. It requires no small amount of devotional credulity to recognise the likeness or to believe the story.

But there is no need for having recourse to such ecclesiastical legends in order to produce a solemn impression in this chamber. Its classical associations are sufficient of themselves to powerfully affect the imagination. There is no reason to doubt the common belief that this is the identical cell in which the famous Jugurtha was starved to death. The romantic history of this African king is familiar to all readers of Sallust, who gives a masterly account of the Jugurthine war. When finally defeated, after having long defied the Roman army, his person was taken possession of by treachery and carried in chains to Rome, where he adorned the triumphal procession of his conqueror Marius, and was finally cast into this cell, perishing there of cold and hunger. What a terrible ending to the career of a fierce, free soldier, who had spent his life on horseback in the boundless sultry deserts of Western Africa! The temperature of the place is exceedingly damp and chill. Jugurtha himself, when stripped of his clothes by the executioners, and let down into it from the hole in the roof, exclaimed with grim humour, "By Hercules, how cold your bath is!" A more hideous and heart-breaking dungeon it is impossible to imagine. Not a ray of light can penetrate the profound darkness of this living tomb. Sallust spoke of the appearance of it in his day, from the filth, the gloom, and the smell, as simply terrific. The height of the vault is about sixteen feet, its length thirty feet, and its breadth twenty-two feet. It is cased with huge masses of volcanic stone, arranged in courses, converging towards the roof, not on the principle of the arch, but extending horizontally to a centre, as we see in some of the Etruscan tombs. This peculiar style of construction proves the very high antiquity of the chamber.

This cell played the same part in Roman history which the Tower of London has done in our own. Here, by the orders of Cicero, were strangled Lentulus, Cethegus, and one or two more of the accomplices of Catiline, in his famous conspiracy. Here was murdered, under circumstances of great baseness, Vercingetorix, the young and gallant chief of the Gauls, whose bravery called forth the highest qualities of Julius Cæsar's military genius, and who, when success abandoned his arms, boldly gave himself up as an offering to appease the anger of the Romans. Here perished Sejanus, the minister and son-in-law of Tiberius, who was detected in a conspiracy against the emperor, and richly deserved his fate on account of his cruelty and treachery. Here also was put to death Simon Bar-Gioras, the governor of the revolted Jews during the last dreadful siege of Jerusalem, who was taken prisoner, and after gracing the triumph of the emperor Titus at Rome, shared the fate which usually happened to captives after such an exhibition.