backwards by the respirators of Paul V., who repaired it, from his
fountain on the Janiculum in Rome across Monte Mario to La Storta, and a
little beyond it to the junction of the roads from Viterbo and Bracciano.
Here the present road follows a winding course for the sake of better
gradients, but the old one (_Clodia_) followed a more direct line in a
cutting through the hill, to the left of the present road, as may be seen
by the old paving-stones at intervals; and here, instead of the clumsy
respirators of Paul V., are wells only, one of which is near the present
road at the junction. The respirators are built over old wells, and serve
to shew that Paul V. restored the _specus_ from La Storta to Rome only in
this part. There are no respirators beyond that point for some distance,
but the _specus_ may still be traced by the wells descending into it.
About two miles further on, this _specus_ is carried on an arcade across
a valley, and it may be traced from thence to the point where Nibby
explored it in 1826, near the lake of Bracciano. From the Osteria Nuova
(fifteen miles from Rome) to La Storta (ten miles from Rome), the rough
pyramids continue along the line of the aqueduct, and at the Osteria
itself there are two of different dimensions close together at the end
of the house or _castellum aquæ_; one is nearly double the size of the
other, and both are of very rough construction. Probably one of these is
of the time of Trajan, the other of the time of Pope Paul; these wells,
with the smaller pyramids over them, are continued to near La Storta;
here a change takes place, and the respirators are modern, as has been
said.
Procopius expresses his amazement at the quantity of water thus brought
to the top of the Janiculum, and poured in torrents over the whole of the
region of the Trastevere. This is still the case, and the fountains in
front of St. Peter’s and in the gardens of the Vatican, are also supplied
from this aqueduct. The water is so abundant that it is even brought over
the bridge and supplies a fountain on the other side.
Paul V. also mentions (in his inscription at the fountain above S.
Pietro in Montorio) that it had been previously restored by one of his
predecessors, Hadrian I., A.D. 774. This was after it had been damaged
by the Lombards under Astulfus, as recorded in the Pontifical Registers
of Stephen III., Hadrian I., and Gregory IV., in whose time (A.D. 830)
the work was completed. The Saracens again destroyed it in 846, and it
was again restored by Nicholas I. (A.D. 860). It continued in use in the
fifteenth century; but in the sixteenth it was much out of repair, and
the branch to the Janiculum almost entirely failed. That to the Vatican
continued to flow in 1561, and was repaired by Pius IV., as recorded
on an inscription in the garden of the Vatican. In 1618, it had become
almost entirely ruined, and was restored in a more thorough manner at
great expense by Paul V., a member of the wealthy Borghese family, from
whom it is now commonly called the Aqua Paola. The Orsini family, to whom
the lake Bracciano belonged, contributed 2,000 ounces of water daily
from that lake. Hadrian I., who had made the first great restoration of
this water-course, was a Colonna, so that three of the greatest medieval
families of Rome have contributed towards it.
The cascade which now falls down the face of the Janiculum, in a
_specus_, turns the water-wheels of three mills in its course; this is
mentioned by Procopius, they having been destroyed by the Goths, and
their place supplied by other mills made in the Tiber by Belisarius,
which continued in use for a long period. The ruins still visible in the
river, opposite the mouth of the Cloaca Maxima, are supposed by some to
have belonged to these mills. They were of wood only[168], and may have
been built on the stone foundations; but these ruins in the river more
probably belonged to the fortifications at the head of the Port of Rome,
where there was a chain across the river to prevent boats from being
carried down by the rapid stream into the Port[169].
Immediately outside of the Porta S. Pancrazio the _specus_ forms the
boundary of the beautiful garden of the Villa Pamphili-Doria, on the
northern side, for about a mile. It is faced with fine reticulated work
of the time of Trajan, excepting where it has been clumsily repaired with
brick in the time of Paul V., and it has a wall built upon it. Shortly
after passing the limits of the garden, it arrives at the old junction
or fork where the stream was divided into two branches, one going to
the fountains in front of S. Peter’s and the Vatican, the other to the
great fountain rebuilt by Paul V. above S. Pietro in Montorio, as before
mentioned. In this part the _specus_, being above ground, had been much
mutilated, and the engineers of Paul V. found it more convenient to
change its course and make a new _specus_ for a short distance, than to
repair the old one. The ancient reservoir and the fork in the _specus_
were abandoned, and new ones made about a hundred yards off, on rather
a higher level. The old reservoir or _castellum aquæ_ was turned into a
farm-house, by piercing the walls with windows and doors, and putting
on a new roof. The original arrangement for the separation of the great
stream into two smaller ones may still be seen in the farm-yard. The old
_specus_ is here just below the level of the ground, with its reservoir,
but there is an opening into it. A portion of it can also be seen under
the Villa Spada, just within the Porta di S. Pancrazio. From the point of
junction, or rather of division, to La Storta, and nearly all the way to
the lakes, the _specus_ is underground; but the line of the branch added
by Trajan can be traced by the respirators as far as the junction, ten
miles from Rome, where, in the year 1830, an inscription[170] was found
on the Via Claudia, near the tavern of La Storta, stating that Trajan had
carried this water into the city at his own expense in A.D. 109. In the
inscriptions put up by Paul V. after his repairs, A.D. 1611[171], the
Alsietina, Sabatina, and Trajana are all considered as the same.
XI. TRAJANA OR HADRIANA[172] (?), (A.D. 120).
“In the time of the Emperor Nerva the health of the eternal
city was sensibly improved by the increased number of
castella, public works and buildings, and cisterns. Nor was
his generosity less for the benefit of private individuals,
so that those who had previously timidly obtained water in an
unlawful manner were now allowed to do so by his favour. Lest
some of the waters should perish uselessly great cleanliness
was adopted, and there was better ventilation, and the causes
of the bad climate for which the city was formerly infamous
were removed. I must not pass by the necessity for a new
distribution of the waters; but this, with the increased
quantity we have added, can easily be arranged, that is, when
the work is completed[173].”
These and other passages in the work of Frontinus shew that great works
were carrying on under his direction, not then completed, their object
being to improve the quality of the water, and to supply an additional
quantity in case any of the existing aqueducts should fail, as they
did occasionally, and to increase the power of distributing it, with a
view to improving the climate. This is a proof that Malaria existed at
that time[174], and that the best remedy for it was an abundant supply
of water in the hot weather, for which the subterranean aqueducts were
most useful. The improvement of the Aqua Alsietina, and the addition of
the Sabatina, were not sufficient for both these purposes; and, as they
supplied the district of the Trastevere only, this could not be all that
was intended by Frontinus in describing the great works begun by him
under Nerva, carried on by Trajan, and completed by Hadrian. The only
work which will correspond to this account is the great aqueduct called
by modern writers the Aqua Alexandrina, and erroneously attributed to
Alexander Severus only.
The sources of this aqueduct are about three miles from Gabii in a watery
meadow, nearly under La Colonna, the ancient Labicum. The reservoir of
the Aqua Felice is in the same meadow, very near that of Hadrian. Several
of the springs that supplied that of Hadrian were intercepted by the
engineers of the Aqua Felice, who mistook these springs for those of the
Aqua Marcia, shewing their ignorance of the line of the aqueducts. One of
the streams, which is rapid and has a considerable body of water, is not
used, because the water is of bad quality, and is so full of chalk that
it is a petrifying stream. The first central _castellum_ and _piscina_
of Hadrian remains nearly intact, lined with the usual brickwork of
that period, but much disguised in outward appearance. It is divided in
the inside by a rough stone wall, as was frequently the case; the upper
chamber to it has an external staircase added, and windows pierced in
it, giving it now the appearance of a mere farm-house. Here the _specus_
is perfect, and from hence it goes at first on a substructure, then on
an arcade across the fields, and along the line of arcade to the Cento
Celle. The part near the reservoir is destroyed, as is the opposite
end near that place, but great part of the arcade in the intervening
portion remains nearly perfect, and is one of the finest arcades of
the aqueducts, extending for miles across the country between the Via
Gabina and the Via Labicana. In some places it is double, one arcade
over another, to cross a low valley or a stream. At about a quarter of
a mile from the source, the _specus_ is open in two places, so that a
man can walk along it, being nearly six feet high and three wide. Small
openings have been left on the sides of the _specus_ at regular intervals
to let the chalky water escape; and in falling from above it has left
the marks of a small cascade in each place, in the form of stalactite, a
solid deposit of chalk or lime or tartar against the side of the piers,
down which it ran. These petrifactions continue all along the line as
far as Cento Celle, and near that point there is a part where the stones
and bricks of the arcade have been carried away for building-materials,
and the masses of hard chalk remain standing up from the ground, in
small pyramids, having very much the appearance of concrete respirators
belonging to a subterranean aqueduct; but this appearance is deceitful.
There is no pipe in them; they are merely petrifactions formed by the
deposit of the chalk from the water.
By the side of the line there are some fine _piscinæ_ and reservoirs,
of _Opus Reticulatum_, at intervals, belonging to the time of Trajan
or Hadrian. Some of the arches near the sources seem to be earlier. The
brickwork is so fine that it appears more like the work of Nero; but most
of the work agrees well with the time of Hadrian, and Visconti states
that an inscription of Hadrian[175] was found at the reservoir in his
time, towards the end of the eighteenth century, and given up to the
Borghese family, the proprietors of the ground, who also drained the
lake of Gabii, with the aid of Canina the architect. This inscription is
believed to have been sold to the French, with other things.
The character of the construction of the _castella_, or reservoirs, does
not agree with the time of Alexander Severus, but suits perfectly well
with those of Nerva, Trajan, and Hadrian, whose works are so well known.
It is work of the first or second century, not of the third. It does not
follow the line of the Via Gabina, but is carried at once to the south of
it, towards the Via Labicana, and passes nearly parallel to it between
those two roads until it crosses the Via Labicana at five miles from
Rome, at the place called Cento Celle.
The bad effect of the petrifying stream was noticed by the engineers of
the Aqua Felice, and, as that stream was carefully excluded by them, it
now runs to waste through the meadows. This discovery was probably made
before the third century, and the _specus_ being then found to be choked
up with stalactite, was restored to use on a higher level by Alexander
Severus. Although the _castella_, or reservoirs, are all of the time
of Trajan and Hadrian, the _specus_ and the arcade to carry it is of
two periods, the later portion of it being of the third century. The
principal intention of this aqueduct has been originally to supply the
great villa of Hadrian at Cento-Celle, but a branch of it does appear to
have been brought into Rome. Although it is very difficult to trace it
for the last two miles, this may arise from the general use of all the
aqueducts near Rome as quarries, by the engineers of the Aqua Felice.
In the excavations made in 1871, in the high ground near the Minerva
Medica, between the Porta Maggiore and the Porta di San Lorenzo, by
the side of that portion of the Marcian arcade that has been mentioned
as found there, was also part of another arcade of an aqueduct of the
third century, which may have belonged to this, and it was in that
neighbourhood that the inscription belonging to the aqueduct of Severus
was found.
About a mile nearer to Rome, at the Torre Pignattara[176], or Mausoleum
of S. Helena, there is a branch from the Marrana, passing under the Aqua
Marcia, apparently to convey water to an imperial villa. The construction
of the arcade of this branch to the south of the road is not of the same
period as that of the other arcade on the other side to the north. It
is usual for modern topographers, following Fabretti, to consider this
branch a continuation of the Aqua Alexandrina; but as the water from the
Marrana, which is at a considerably lower level than the Aqua Marcia,
runs _down_ the gentle incline of this arcade towards the road and the
Mausoleum of S. Helena called Torre Pignattara, this is impossible. The
construction is chiefly of the fourth century. The Mausoleum of S. Helena
is on lower ground than this part of the Marrana.
Constantine is said to have built a villa for his mother near her tomb;
but there are no remains of an imperial villa nearer than those called
the Cento Celle, a mile further along the road, or the one called “Torre
de’ Schiavi[177],” i.e. Tower of the Slaves, about a mile across country,
on another road, but on the same level. A milestone for the third mile,
found opposite this mausoleum, with an inscription of the time of
Maxentius, has been published by Ciampini. This indicates that some works
were going on there at the end of the third century, and the arcade may
be of that period.
A large and a very remarkable reservoir of the time of Trajan or Hadrian
remains a little to the west of the mausoleum, and on rather higher
ground. This was probably to receive the water for a branch to the
imperial villa, afterwards taken possession of by the Gordiani, who built
at that place their great family mausoleum, on which a tall medieval
tower was afterwards erected; of this, very picturesque ruins remain,
under the title of Torre de’ Schiavi. There are at the same place other
large reservoirs of the time of the Gordiani, shewing that the great
imperial villa was still supplied with water from the Marcian aqueduct in
the third century.
No water under the name of Hadrian is mentioned in the Regionary
Catalogue of the fourth century, it is therefore evident that this great
aqueduct was not called then after that emperor, although we are told
in his life by Spartianus, that many were made in his time, and were at
first called after him (as we have said[178]). At the first reservoir,
the starting-point, there was an inscription of Hadrian, and the other
reservoirs belonging to it are also constructions of the same period.
It may be that this water did not come into Rome at all, but that the
aqueduct was made to supply the great villa in the place now called
“Cento-Celle,” to which it leads in a direct line, and where it appears
to terminate. If any alterations were made, these may have been done in
the time of Alexander Severus, and this may now represent the so-called
Aqua Alexandrina, as Fabretti thought, although he was certainly mistaken
in one part of his account of it. The branch which went by the Mausoleum
of S. Helena, and which apparently ran underground to the Villa of the
Gordiani, was not a branch of the aqueduct to convey water into Rome, but
a branch from the great aqueduct for the villa or villas, as it now does
from the Marrana at a lower level. This short arcade is of the time of
Constantine. The great and long one that leads to the Cento-Celle is of
two periods, the earlier part of the time of Hadrian, the latter of the
third century. It is quite possible that the original _specus_ had become
choked up with stalactite in the course of a century, and that it was
restored to use for a time by Alexander Severus, and so called after him.
THE BRANCH OF TRAJAN ON THE AVENTINE.
It has been mentioned in the account of the Anio Novus (IX.) that, after
the main conduit reached the great reservoir at the arch of Dolabella, it
was divided into three branches, and that one of these was not completed
until the time of Trajan and Hadrian. This important branch was carried
over the valley between the Cœlian and the Aventine on a lofty arcade,
built upon the _agger_ of Servius Tullius, and over the Aqua Appia, also
passing over the Via Appia upon the arch of the Porta Capena to the
Piscina Publica. It then ran along the edge of the cliff to the north
of S. Balbina, and crossed again the valley between the Pseudo-Aventine
and the Aventine itself, a little further to the west, by the side of
the road which goes down the hill towards S. Prisca. In the vineyard
of S. Prisca a portion of the _specus_ remains perfect, at a very high
level[179]. From thence it was carried across the hill to the cliff above
the Tiber, where the monastery and garden of S. Sabina are now placed.
These are on the site of a palace of the time of the early Empire. Some
extensive and important excavations were made there in 1855-57, by the
Dominican monks of S. Sabina, and among the discoveries then made were
an extensive series of conduits, with a _piscina_ and a _nymphæum_ of
the same period,—of the end of the first and the beginning of the second
century of the Christian era. A cascade _specus_ served to conduct the
surplus water down to the more ancient cave reservoir at the mouth of the
Aqua Appia, at the Salaria. An account of these excavations was drawn
up by M. Descemet[180], and published in the Memoirs of the Institute
of France, with an excellent plan and section. Several brick-stamps, of
which the words are given in that work, with the names of the consuls,
and some terra cotta water-pipes, with the name of Trajan, were also
found here. Others were discovered on the Aventine and near the same spot
by Fabretti, who was puzzled by them, because they did not agree with
his theories about the aqueducts. Donatus also mentions some of the same
facts as known in his time. Some of the bricks were made at the kiln
(_figlina_) of Annius Verus, said to have been on the Aventine, near
the Salaria; and, if this is correct, that was the spot where they were
found. Others have the stamp of Trajan himself. Another is the work of
an Arabian servant of Q. Servilius Pudens, A.D. 139, when the Emperor
Antoninus Pius and C. Bruttius Præsens were consuls. A piece of leaden
pipe, with an inscription upon it, AQVA TRAIANA, was also found on the
Aventine.
XII. AURELIA, A.D. 185, AND XIII. SEVERIANA, A.D. 190.
The Aqua Aurelia of the Regionary Catalogue must be the one made by
Marcus Aurelius to convey water to his villa on the Via Appia, usually
called the Villa de’ Quintilii, where a brick-stamp of the time of Marcus
Aurelius (A.D. 162) was found on the aqueduct itself by Fea in the
eighteenth century[181]. This water was afterwards conveyed to Rome by
his successors, Ælius Aurelius Commodus and Septimius Severus, to supply
the great _thermæ_ begun by Commodus and finished by Septimius Severus,
which were in the first Regio just inside of the Porta Latina, and must
have been begun about A.D. 185[182].
The Aurelia was an important aqueduct, and there are slight remains of
its _piscina_ just outside of the Porta Latina on the southern side: its
_specus_ was traced nearly to that point in the excavations made in 1871.
The modern road is cut through this old _piscina_, forming a foss-way
in this portion: the aqueduct there passes underground, and has been
destroyed or is not visible in this part; but, about a mile from Rome,
it can be seen on the bank in the western cliff of the valley of the
Caffarella. The _specus_ remains as a tunnel for a short distance, and
this was laid open at both ends in 1872 under my direction; it had been
concealed and covered over with Pozzolana sand, which had fallen over it
from the cliff above, but it can now be seen again. The greater part of
the _specus_ has been destroyed, and used for building the large modern
farm-house on the opposite side of the valley, the building material
having been good brick. As it would not pay to destroy the tunnel, that
was let alone.
These remains of the _specus_ are near the well-known tomb called Dio
Ridicolo. To this point it runs along the bottom of the valley at the
foot of the hill on the side of the small stream or Marrana, here
artificial, and parallel to that branch of the river Almo. This open
conduit was probably made in the twelfth century, at the same time that
the other branch of the Almo, which runs through Rome, was altered and
made into a canal or mill-stream where necessary, in order to keep up a
constant supply of water, and to avoid its being wasted in floods.
Let us now trace this aqueduct _backwards_ from Rome, in that part near
the city. At the Nymphæum, called the fountain of Egeria, it turns at a
sharp angle up to another small _castellum aquæ_, close to the church
of S. Urbano, which is usually mistaken for a tomb; but the walls are
lined with _opus signinum_ or _coccio pisto_, the invariable test of an
aqueduct. At this point it turns again towards another fine _castellum
aquæ_, at the end of the Circus of Maxentius and of his son Romulus. It
comes on there from the head of the valley of the Caffarella, and to that
point from the villa of the Quintilii in the Via Appia Antiqua. Thus far
we have traced its course _backwards_ from the _thermæ_; in order to
identify it more clearly, we will now go to the sources, and bring it
down to the same point to which we have traced it from the _thermæ_.
The sources or springs are on the side of the hill of Marino, below
Grotta Ferrata, in the same swampy district as those of the river Almo,
and of the old aqueducts of the Tepula and the Julia. Several springs
are collected into a central reservoir; and, as is usual with other
aqueducts, they are then brought into a _specus_, at first underground
to the foot of the hill, then upon an arcade, of which there are
considerable remains at the Torre di Mezza, Via di Albano, about seven
miles from Rome. This fine arcade of the third century goes on to the
villa of the Quintilii, and was no doubt built under Aurelius Commodus,
after he had obtained possession of that great and fine villa. In various
parts of that great building are remains of reservoirs for this aqueduct,
and of baths connected with them[183]. About half-a-mile nearer to Rome
is, at an angle, as usual, another large reservoir, which has been turned
into a farm-house; and the appearance of a medieval chapel or church
has been given to it, by building a tower at one end. Possibly it was
used for that purpose in the Middle Ages. From thence to the head of the
valley of the Caffarella is but a short distance. Where the _specus_ has
been carried on an arcade above ground, it has been destroyed as a quarry
for the good old bricks; where the ground is higher and the _specus_ is
underground, it has been traced in parts only.