c. Fora of the Emperors.
In the plain to the N.E. of the Forum of the Republic lay the
Fora of the Emperors, which were erected not only as monuments
to their founders and ornaments to the city but also for judicial
proceedings and other practical purposes. Their chief edifice was
always a temple. The Forum Julium, the first of the kind, was begun
by Cæsar and completed by Augustus; the second was built by
Augustus. A third, around the Templum Pacis, was constructed
by Vespasian. Between this forum and the first two lay the Forum
Transitorium, begun by Domitian and completed by Nerva. The
series ended on the N. with the magnificent Forum of Trajan.
We begin our inspection at the N. corner of the Forum Roma-
num, where the Via dell' Arco di Settimio Severo (p. 273), de-
scending from the Capitol, unites with the Via di Marforio (p. 233).
Here, in the Via di Marforio, lies the small church of San
Giuseppe dei Falegnami (Pl. II, 20), which is built over the
Carcer Mamertinus, one of the most ancient structures in Rome
(entrance below the outside steps, from 9 till dusk, 25 c.; electric
light). This was perhaps originally a well-house (Lat. 'tullianum'),
traditionally attributed to the king Servius Tullius (p. xxxi), and
was afterwards used as a prison. A theory has recently been ad-
vanced that the building really was an archaic bee-hive tomb (like
those of Mycenæ).
The building consists of two chambers, one below the other. The
upper is an irregular quadrilateral, which was probably once adjoined by
other similar chambers. An inscription on the front records a restoration
under Tiberius or Caligula. The lower chamber, which was originally
accessible only through a hole in the ceiling, is 19 ft. long, 10 ft. wide,
and 6 1/2 ft. high. The original vaulting was probably conical, formed by
the gradual projection of the side-walls until they met, but the present
roof is a flat arch of jointed blocks of tufa. In this dungeon perished
Jugurtha, Vercingetorix, and other conquered enemies. Sallust, in re-
cording the execution of Catiline's confederates, describes the prison
almost exactly as it now exists: 'In the prison is a chamber named
the Tullianum, about 12 ft. below the surface of the ground. This is
surrounded by walls and covered by a vaulted stone roof; but its appear-
ance is repulsive and terrible on account of the neglect, darkness, and
smell.' — It contains a spring, which, according to the legend, St. Peter,
who was imprisoned here under Nero, miraculously caused to flow in
order to baptise his jailors. The building has therefore been named
San Pietro in Carcere since the 15th century.
A little to the E. the Via Bonella reaches the Forum. At its
entrance, to the right and left, are the churches of Santa Martina
e Luca and Sant' Adriano (p. 295). Santa Martina e Luca
(Pl. II, 20) consists of a lower and an upper church. The present
lower church, which possesses an elaborate baroque altar by Pietro
da Cortona, was originally built in the 7th cent. in the ruins of the
Secretarium Senatus (p. 295). It was rebuilt about 1640, partly at