The archæology of Rome, Part 8

by John Henry Parker

Each of these fortified camps was surrounded by a great wide and deep foss or trench. These great banks and trenches are usually mistaken for natural hills and valleys; but natural hills and valleys are not merely high banks fifty feet high and perhaps a hundred feet wide, nor are natural valleys long narrow trenches of the same dimensions, running on each side of the great banks, being in fact the trenches from which the earth has been thrown to form the banks. Such a bank with such trenches can be clearly traced all round Rome by eyes that are accustomed to examine such things, although modern buildings have disguised them so much that an ordinary observer does not see them. People cannot see over modern walls of twelve feet high, still less over the great Wall of Aurelian fifty feet high, and they do not think of comparing the level of the ground on each side of that wall, nor can they easily do so. These great ancient earthworks were extremely convenient for the engineers of the Aqueducts, which were brought upon the high banks at the farthest corner. They were carried along the bank on the north side of the Sessorium, from its north-east corner to the south-west angle, where the great bank of the Tarquins joins on to it. Some branches of the Aqueducts, perhaps the main stream in some cases, were then carried along this high bank of the Tarquins to the north, as far as the other Prætorian Camp, and beyond it along the outer wall of Rome, as we have seen in the case of the Anio Vetus, the Marcia, Tepula, and Julia. These did not pass through the Sessorium, but parallel to it about a hundred yards on the north of it. The Claudian arcade had been at about that distance on the north of it, all the way from the Piscinæ into Rome. The Marcian arcade was made nearly over the Anio Vetus, which ran between that arcade and the Claudian, but much nearer to the Marcian.

On entering Rome, this main stream went straight on through the great bank to the large reservoir on the inner side. The reservoirs for the Tepula and Julia were much to the north, near the Porta di S. Lorenzo (the Porta Viminalis of Frontinus), as we have seen; that of the Marcia was much closer to the Porta Esquilina. The two great reservoirs, called by Frontinus the Gemelli, were made in the great foss between the Sessorium (S. Croce) and the Cœliolum (the Lateran). They had probably been originally made for the Aqua Appia and the Anio Vetus, being both at a low level, though one was much deeper than the other. Advantage was taken of these ancient reservoirs to erect the higher one required for the reception of the waters of the Claudia and Anio Novus over it, or by the side of it, as was very usual throughout Rome. The later reservoirs are always made nearly over the old ones. This is equally the case here at the entrance into Rome and at the other end of the Cœlian. The great high reservoir of Nero is close by the side of, and really over, the great subterranean reservoir of the Aqua Appia (now under the garden of the Villa Cœlimontiana, as described in the account of the Appia).

The foregoing explanation seems necessary to explain the photographs that now follow, belonging to the Arches of Nero. The first of these (No. 77) shews the junction with the Porta Maggiore; the two specus that pass over that great gate are visible to the right of the photograph. The beginning of the Arches of Nero is then seen, where they have to cross the great wide and deep foss of the Sessorium, and were therefore strengthened by sub-arches, as seen in No. 76. A more close view of these arches, nearly at the same point, is seen in 66.

These arches were used by the engineers of the Aqua Felice whenever they suited their purpose, and cut about or destroyed without mercy; they also made use of an old specus to carry their metal pipes whenever it was convenient to do so, and the old specus that ran along the Cœlian was very convenient for that purpose. 1295* is from a drawing made to shew this. The specus of the Aqua Felice was first carried on the lower arches of the double arcade of Nero, the upper part of the arcade being destroyed. The metal pipes were then carried down into the old subterranean specus (the Specus Vetus of Frontinus). This is in the same garden or vineyard as the Gemelli, in the great foss between the Sessorium and the end of one of the banks of the Tarquins, (on which the garden of the Villa Volkonski has been made, and along which the Arches of Nero run.) A portion of the grand arcade, with the specus very visible on the top of it, is shewn in 759. This is close to the Scala Santa of the Lateran; the arcade carrying the aqueduct passed along the bank on the north side of the Lateran fortress on the Cœliolum, and supplied that with water.

On the western side of the Lateran fortress is another great foss, between the Cœliolum and the east end of the Cœlian Hill. It was either thought more convenient to make a bank across that great foss for the aqueduct to rest upon, or this bank which traverses that great foss had been made before for an upper road, and was used first for the Aqua Appia and the Anio Vetus, and afterwards by Nero. The existence of such a foss between the east end of the Cœlian Hill and the Cœliolum is denied by those who have not paid attention to the subject, and have not been into the gardens and vineyards to examine it; but the fact is a matter of demonstration. The tomb of the first century (miscalled the House of Verus, probably a tomb of the great Lateran family), being on the western bank of that fortress and the eastern bank of the foss, and the other tomb of the first century also, in the garden of what was the Museum of Campana (under an arch that carries the modern road), on the western side of that great foss, are a demonstration that there was such a foss on the east side of the City of Servius Tullius, i.e. that the Cœliolum and Lateran did not form part of the City at that time. (See my chapter on the Tombs, and the photographs of these two tombs, 174 and 1942).

The Arches of Nero remain on the Cœlian in many parts of the line, by the side of the road from the Lateran to S. Stefano Rotondo and the Navicella, with the arch of Dolabella, which was under the great reservoir of Nero, and formed the entrance of the Claudium. The Arches of Nero are faced with the finest brickwork in the world (ten bricks to the foot, as usual at that period, and are chosen as typical examples). This is well shewn in 78, and the internal construction of rubble, faced only with the fine brickwork, in 358. A line of these, shewing the picturesque effect, is shewn in 131 and 357. The aqueduct formed one of the usual angles between the Lateran and the arch at the west end of the Cœlian. It has been destroyed in this part; but this accounts for the arches being sometimes on one side of the road and sometimes on the other.

We have now arrived at the arch of Dolabella, built when he was consul, A.D. 10, as an entrance to that part of the Cœlian Hill which had been the keep when it was a separate fortress, and was afterwards made the Claudium. This arch is of very simple construction, of travertine, the same construction as the early part of the Basilica Julia, built by Julius Cæsar and Augustus. It was used by the engineers of Nero as a foundation for their great reservoir, or rather for one corner of it, as we clearly see in 72. The work of the time of Nero terminated here, but the design was carried on by his immediate successors. The water was then divided into three branches; the one on the right hand, to the north, went to the great reservoir between the Cœlian and the Esquiline, called the Stagna Neronis, and was used for the sham naval battles. Around these Stagna the Colosseum was afterwards built. A portion of the arcade on which the specus was carried is visible in the garden of the monks called the Passionists of SS. John and Paul, and is well shewn in No. 1773, looking towards the east, with the ruins of the reservoir over the arch of Dolabella, and the church of S. Stefano Rotondo in the distance. There are remains of a reservoir for this, of the third century, in the garden of the monks on the terrace of the Claudium, opposite to the Palatine, shewn in No. 1765. The ruins of the fine arcade of the Claudium stand on this terrace; the specus also is in a wall here, behind the arcade. A portion of another reservoir or piscina for them can be seen at the foot of the cliff of the Claudium, at its north-east corner, opposite that part of the Colosseum near the Meta Sudans; this is also shewn in No. 1743, with opus reticulatum of the time of Nero. This branch continued in use in the third century; for there are remains of another reservoir for it, again at the foot of the Claudium opposite to the Colosseum, but more to the east, near the north-east corner of the Claudium, and near to the eastern end of the Colosseum. The remains of this reservoir are shewn in No. 1735. A colonnade carrying the specus from this reservoir to the second story of the Colosseum, is shewn on one of the coins of Septimius Severus, who probably built this reservoir. In the corridors of the Colosseum are open stone troughs lined with the cement for water. These carried water from this aqueduct in a constant running stream to cool the air. They are work of the third century, with old inscriptions on some of them, shewing that they were made of old materials.

Another branch from the great reservoir went straight across to the Palatine, and from thence to the Capitol; it first follows the line of the road down the Clivus Scauri, on the left or southern side, and a fragment of it is visible opposite to the church of SS. John and Paul, as seen in No. 305. At the foot of the Clivus Scauri it formed an angle, and passed against the cliff on which the apse of the church was afterwards built; it now forms the lowest and last of the series of arches that are carried across the road to support the side of the church. Then, after this angle to the north, it resumes its course to the west upon the arches across the valley to the Palatine, which was a double arcade; but the lowest tier of it only remains, as is shewn in 116. A portion of the upper tier is also visible at the end of it; an arch of this upper tier remains, which, having been made into a back gate of the Palatine, has been suffered to remain, and is shewn in No. 72. A large reservoir for it was made at the south-west corner of the Palatine, on which the palace of Commodus was afterwards built; part of this reservoir and specus is shewn in 683 (made from a drawing). The specus went across the middle of the Palatine, and has been found more than once in some of the recent excavations, but not understood. It was then carried on the bridge of Caligula to the Capitol, a small portion of which remains connected with his palace, as is shewn in Nos. 1447 and 1451.

The third branch from the great reservoir over the arch of Dolabella on the Cœlian was made in the time of Trajan, to carry water to supply the thermæ on the Aventine, called after Sura, the cousin of the Emperor; these thermæ were closely connected with the private house of his family, rebuilt in his time, and called in the Regionary Catalogue “Privata Trajani,” of which there are considerable remains, now subterranean. The first place where this branch of the aqueduct is visible is in another reservoir (1147) against the cliff of the Cœlian, opposite to S. Balbina. This is partly above the level of the hill, and has been thought part of the Palace of Commodus, on the Cœlian (which may possibly have been built over it, but the existing remains are of the time of Trajan). The lower part is under this, and is excavated in the cliff. These were brought to light in the excavations of A.D. 1868 (559, 1008, 1009, 1010, 1011). The plan and section of it are to be seen in 1150*, 692*. Against the cliff the aqueduct formed one of the usual angles towards the north, and this was carried across the valley on the agger or bank of Servius Tullius, first passing over the arch of the gate of the Porta Capena, above the Aqua Appia, on a much higher level, and on an arcade, probably a double arcade, like the Arches of Nero near the Porta Maggiore, on account of the great height at which the water had to be carried from one hill to the other. All that remains of this lofty arcade is a line of brick piers passing across from the Cœlian to the Aventine, over the Aqua Appia, before described, and passing by the north end of the Piscina Publica, as rebuilt in the time of Trajan over the old one, which had belonged to the older aqueducts. There are considerable remains of the walls of this period, that divided the chambers shewn in 557, 558, 1288.

This arcade can then be traced against the cliff of the Pseudo-Aventine, on the north side of S. Balbina, though partly concealed by the filling up of the space against the cliff before mentioned. The tall arcade then crosses the valley from the Pseudo-Aventine to the other part of the Aventine, and from the garden of S. Balbina to that of S. Prisca, and, in the latter garden, there are considerable remains of it on the cliff opposite to the Palatine. At the north end is the specus upon the arcade (the top is open, and there is a walk upon it), 79. A small portion of the Thermæ of Sura is also shewn, with the specus in front of the ancient wall of tufa, called the Wall of the Latins (833).