THE QUIRINAL HILL--BATHS OF DIOCLETIAN--AGGER OF SERVIUS--CASTRA PRÆTORIA.
[Sidenote: Baths of Diocletian.]
The broad flat space to the N.E. of the Quirinal Hill, was occupied by the
Thermæ of Diocletian, now converted into the great Church of S. Maria
degli Angeli. This enormous group of buildings was the most extensive of
all the gigantic edifices of the empire, and the ground plan is not
difficult to trace by the aid of the existing ruins. Some idea of their
dimensions will be given by remarking that the grand court enclosed a
space once occupied by the church, monastery, and spacious garden of the
Monks of S. Bernard, the great church and monastery of the Carthusians,
two very large piazzas the large granaries of the Papal Government, part
of the grounds of the Villa Montalto Negroni, and some vineyards and
houses besides. The north-western side of this grand court is now only
marked by the remains of two semicircular tribunes in front of the railway
station. The rest of the foundations of this side are hidden under the
great cloister of the Carthusian monastery, and in the district beyond.
The principal entrance was on this side. The south-eastern side is now
occupied by the buildings of the railway station, at the back of which
were discovered the ruins of a large reservoir now destroyed (K), in the
shape of a right-angled triangle. The peculiar form of this building seems
to have been necessitated by the course of a public road of some
importance confining it on the south side, and it has been supposed, not
without reason, that this was the principal road leading out of the city
at the Porta Viminalis. The interior was filled with pillars like those
which still stand in the ancient reservoirs at Baiæ and Constantinople.
[Illustration: The Quirinal Hill, as seen from the Palatine.]
On the south-western side of the court there are considerable remains. In
the gardens of the monastery of S. Bernardo, part of the cavea of a
theatre (A) with a radius of about seventy yards, may be traced, not
unlike that in the Thermæ of Titus. The seats of this are gone, but
parts of the back wall with niches remain. On each side of this are traces
of rectangular chambers, and at the corners stand two round buildings,
one of which is nearly perfect, and has been converted into the Church of
S. Bernardo. The ancient domed roof with its octagonal panelled work is
still standing. Part of the other rotunda at the southern corner is also
left, and has been built into the end of the Via Strozzi.
[Illustration: THERMÆ DIOCLETIANÆ. (PALLADIO.) _The red lines mark the
conjectural restorations._]
The north-western side of the court ran parallel to the Via di Venti
Settembre from the Church of S. Bernardo. It contained, according to
Palladio’s plan, two semicircular exedræ (LL) for philosophical
conversation or disputation, and some other rooms the purpose of which is
not known. The Ulpian libraries are said to have been transferred to these
baths from the Forum Trajani. In this spacious court stood a great pile of
buildings, the centre of which was occupied by a great hall (D), now the
church of S. Maria degli Angeli. The pavement of this was raised above the
ancient level of the ground by nearly eight feet, when Michael Angelo
undertook to convert the ancient building into a church, and thus the
bases of the columns remain buried, and new bases of stucco work have been
placed round them. This roof must therefore have been in ancient times
considerably more lofty than at present. The ancient roof was 120 feet
high, and roofed as now, with an intersecting vault in three compartments,
supported by the eight colossal ancient granite pillars. These columns of
Egyptian granite with their Corinthian and composite capitals form the
sole relic of the magnificence of the hall. In the modern church the
transept corresponds to the longer axis of the ancient hall, and the nave
to the shorter. Vanvitelli, who altered the arrangement of the church in
1749, threw out an apse for the choir on the north-east side, and made the
circular laconicum (C) of the old Thermæ serve as an entrance porch.
Antiquarians are not agreed as to the purpose of this great central hall.
Scamozzi, in his edition of Palladio, calls it a xystus for athletic
exercises, but, following the analogy of the Thermæ of Caracalla, the
baths at Pompeii, and some of the other great thermæ, we should rather
suppose it to have been the tepidarium. This view is confirmed when we
notice that the laconicum or sudarium (C) is on one side, and the natatio
(F) for the cold baths on the other, between which the tepidarium was kept
at a mean temperature.
The two wings of the central building were occupied by large peristylia,
with cold piscinæ in the centre of each (EE). Round these peristylia were
built various rooms for athletic exercises, called sphæristeria and
gymnasia.
The style of brick building used in these Thermæ, recalls that of the
Basilica of Constantine, where we see the bricks irregularly and hastily
laid; and the whole of the architectural details which have been preserved
seem to point to the same period. Positive evidence of the date and the
builder is not however wanting. An inscription, which was still to be seen
two hundred years ago in the thermæ, and which has been partially
preserved to us, when compared with three others which were found in the
neighbourhood, shows that Maximianus gave orders for building these thermæ
when he was absent in Africa, during his Mauretanian campaigns, and
intended them to be dedicated to the honour of his brother Diocletian. The
dedication took place after the abdication of Diocletian and Maximianus,
when their successors Constantius Chlorus and Galerius Maximianus had
begun their reign, A.D. 305, but before the death of Constantius in 306.
The old chronologers place the date of the commencement of the buildings
in 302, which agrees very well with the date of the Mauretanian campaigns
of Maximian.
Baronius accounts for the preservation of so large a part of these thermæ
by the statement that they were considered to be a monument of the
Diocletian persecution. There was a tradition, he says, that Diocletian,
after dismissing some thousands of his soldiers because they held the
Christian faith, compelled them to work as slaves in the erection of his
thermæ, and ordered them to be martyred when they had finished the
building. It has also been said that the bricks are in some cases marked
with a cross, but this is not well authenticated.
[Illustration: THE SERVIAN WALLS.]
At the end of the fifth century, the baths are mentioned by Sidonius
Apollinaris as still used, but at the time of the visit of the anonymous
writer of the Einsiedlen MS., probably about A.D. 850, they were
evidently in ruins. Among the ruins have been found, from time to time, a
number of busts of the Emperors Diocletian, Maximian, Galerius, and
Constantine, and also the well-known busts of philosophers now in the
Farnese collection at Naples.
The great fountain now in front of the railway station is supplied by the
water brought along the course of the ancient Aqua Marcia.
[Sidenote: The Servian Agger.]
The Agger of Servius, which has now been so much levelled and destroyed,
ran between the Church of S. Maria degli Angeli and the present walls.
This enormous rampart has been described by Dionysius. He says that the
ditch outside was more than one hundred feet broad at the narrowest part
and thirty feet deep, and that a wall stood upon the edge of the ditch
supported by the agger, which was of such massive strength that it could
not be shaken down by battering rams or breached by undermining the
foundation. Dionysius gives the length of the agger as seven stadia, and
Strabo as six, which, taking the stadium at 202 yards, nearly corresponds
to 1400 yards. The breadth he states at fifty feet. That this ditch and
wall were the work of some of the later kings there can be no doubt, but
it cannot be determined what part each took in their erection. The final
completion of the whole undertaking is ascribed to Tarquinius Superbus,
who deepened the ditch, raised the wall, and added new towers. The
additions made by him can be distinguished in the portion brought to light
by the modern excavations in the railway cutting.[109]
Excavations which have been made in this part of the agger from time to
time, and the extensions of the city in this direction have brought to
light an enormous wall buried in the earth, constructed of huge blocks of
peperino. This is probably the wall mentioned by Dionysius, which in his
time stood outside the rampart on the edge of the ditch. The remains of
buildings of the imperial times have been found placed upon and outside of
this wall, and it is probable that the whole ditch is now filled with such
remains, and most part of the wall buried in them.
The central railway station stands close to this agger, and cuttings have
lately been made through it to make room for the station, by which new
portions of the wall have been disinterred. All these excavations have
proved the truth of Dionysius’s description, the wall having been found on
the outer side of the original agger, which is easily distinguishable from
the rubbish in which it is buried by being composed of clean soil unmixed
with potsherds and brickbats. The wall probably ran from the southern end
of the agger along the back of the Esquiline and Cælian in the direction
of the modern Via Merulana and Via Ferratella. In this portion must be
placed the Porta Querquetulana and the Porta Cælimontana, but their exact
situation is unknown.[110]
[Sidenote: The Prætorian Camp.]
Near the Porta Pia, to the north-east of the church of S. Maria degli
Angeli, the square of the Castra Prætoria projects from the Avails. This
permanent camp was established under Tiberius by Sejanus; subsequently
Aurelian made use of the four outer walls of this camp as a part of his
fortification, and therefore Constantine, when he abolished the Prætorian
Guard, pulled down the side towards the city only. The porta decumana of
the camp is still to be seen though it is now walled up, and also the
porta principalis dextra, but the porta principalis sinistra has
disappeared or perhaps never existed. The camp was enclosed by a wall at
least as early as the time of Pertinax and Julian, for here occurred that
memorable and most melancholy scene in Roman history, when the Prætorian
guards shut themselves within their camp after the murder of the reforming
Emperor Pertinax and put up the throne to auction. Julian and Sulpicianus
were the bidders. The soldiers let down a ladder and allowed Julian to get
up upon the wall, says Herodian, for they would not open the gates before
they heard how much would be offered. Sulpicianus was not allowed to mount
the wall. They then bid one against the other, and at last they ran up the
price little by little to five thousand drachmas to each soldier. Julian
then impatiently outbid his rival by offering at once six thousand two
hundred and fifty, and the Empire was knocked down to him. This was not by
any means the first or only time that the fate of the Empire had been
decided here.[111]
The chief power in the Roman state had lain within these walls of the
Prætorian camp since the time when Tiberius consented to allow their
designing colonel, Sejanus, to establish the Prætorian guards in permanent
quarters, and the readers of the historians of the Empire will recall the
many vivid pictures of their rapacity and violence. To go to the Prætorian
camp and promise a largess to the guards was the first duty of a Roman
emperor.
The eastern side of the camp, which is probably the only one now retaining
its original form, measures 500 yards, and the southern 400 yards. The
latter seems to have been partly pulled down, and the northern side has
also been altered. Aurelian’s Wall did not exactly meet the two angles of
the camp towards the city, but its course was here determined by the
houses and buildings in the vicinity which it was desirable to protect.
The walls of the camp were, according to Bunsen, at first only fourteen
feet high, but were raised by Aurelian and fortified with towers. Some
parts of the walls doubtless consist of the original brickwork of
Aurelian’s time, as the masonry bears the marks of great age, and is of a
most regular and solid style. A few of the soldiers’ quarters are still
left, consisting of rows of small low arched rooms similar to those on the
Palatine and at Hadrian’s Villa near Tivoli.[112]
[Sidenote: Porta Chiusa.]
In the angle formed by the projecting wall of the Prætorian camp and the
Aurelian Wall, there is a gate now walled up and called simply by the name
of the Porta Chiusa. This gate is one of the mysteries of Roman
topography. It is not mentioned by Procopius or by the anonymous writer of
Einsiedlen, yet it seems too large and important to have been altogether
omitted. That a gate would be required here in Aurelian’s Wall, at least
before Constantine’s reign, while the camp was still occupied, seems
probable. No passage would be allowed to the public through the camp, and
besides the Porta Nomentana, another gate would be wanted for the
convenience of persons resorting to the camp from the country with
supplies of provisions, or on business of various kinds, or for the
shopkeepers who would naturally live within the walls near the camp. It
may have been closed when the camp was abolished by Constantine, and that
part of the city became comparatively empty, and it would thus in the time
of Procopius, or the anonymous writer of Einsiedlen, have been long
blocked up and forgotten or perhaps concealed by other buildings. This may
account for their silence.