The archæology of Rome, Part 8

by John Henry Parker

The arcade of Caligula and Claudius, which is entirely of stone, terminates at the Porta Maggiore, the Esquilina of Frontinus. The work of Nero includes the arches within the city from the wall close to the Porta Maggiore to the great castellum on the Cœlian, over the arch of Dolabella. The specus of the Anio Novus is easily distinguished from the specus of the Claudia, as the latter is of squared stone.

The arcade of the Claudia has been considerably repaired with brick, and the arches filled up in several places with brickwork of the time of Septimius Severus and Caracalla, A.D. 193-217. This may be distinctly seen in that part of the arcade which is between two and three miles from the city, near the Porta Furba. It was again repaired by Pope Hadrian I. in 780, and several times by other Popes.

The remains of these two aqueducts, one above the other, are admirably seen in their course along the top of the Porta Maggiore; and at this spot their relative levels with regard to the Marcia, Tepula, and Julia, are also clearly exhibited, the latter entering the wall close to the gate, and almost at right angles to it. Thus, at one view, we are able to see the specus of five out of the nine aqueducts, mentioned by Frontinus, actually remaining. A sixth, the Anio Vetus, also passes under the Walls of Rome at the same point; the specus is half underground, and now concealed by the restorations made in 1869.

An inscription upon the face of the specus itself in the wall of the city over the archway, records that Claudius the son of Drusus, caused to be brought into the city the water of the Claudian conduit, from the springs called Cæruleus and Curtius, from 45 miles distance; also the water of the Anio Novus, from 62 miles, at his own expense[141]. These dates here given correspond with the year 798 of Rome, or A.D. 45. Great repairs were made by Vespasian and Titus to the Claudian aqueduct. The distance from which the Anio Novus is brought, according to this inscription[142], is 62 miles, which agrees with Frontinus[143].

The architect of the Claudian is believed to have been Claudius Annius Bassus, mentioned by Tacitus as chief engineer at Carthage under Marcus Silanus, the father-in-law of Caligula. The remains of the tomb of Bassus may be seen near Vicovaro. The tomb of another architect and his family, on the side of the agger upon which the arcade of Nero stands, near the Porta Maggiore, was excavated in 1865. From its situation immediately under the Neronian Arcade against the bank on which it stands, there seems no doubt that this Tiberius Claudius Vitalis, whose name is inserted on the front of the tomb, was the architect of the arcade; and it does infinite credit to him, for it is one of the finest pieces of brickwork in the world.

This arcade, commonly called the Arches of Nero, carried the specus of the Claudia[144] and Anio Novus combined. It first crosses the foss on a double arcade, one upon the other, to give more height across this wide and deep inner trench; it is then carried on a high bank, and therefore on a single arcade only to the Lateran, and on another bank across the foss between the Lateran and the City to the Cœlian, and along the north side of S. Stefano Rotondo to the reservoir and piscina over the arch of Dolabella. This arch was the principal entrance to that part of the Cœlian in which the Claudium, or courts and temple of Claudius, were situated. There are magnificent ruins of a large castellum aquæ over this arch, faced with the beautiful brickwork of Nero; in part of this the small church of S. Thomas in Formis has been made.

Another large subterranean reservoir remains perfect on the west side of this lofty brick castellum of Nero. This consists of three large vaulted chambers under the garden between the church of the twelfth century and the small monastery of the Redemptorists, now (1872) all belonging to the Villa Mattei, or Celimontana. There is, through the crown of each of the vaults, a circular opening, or well, closed by a stone, which can be moved at pleasure for letting down buckets into the water; it is still used for the purpose of irrigation. From the low level of this reservoir, it must have belonged to the Aqua Appia. By the side of the garden over this, and above ground, in a line with the Arch of Dolabella, is a wall of the first century, faced with reticulated masonry, probably part of the castellum of that period, as new reservoirs have been built there for each successive aqueduct that came to this point. The highest, being that of Nero, was 50 feet above the level of the ground.

Thence the water was distributed in different directions, one branch to the Claudium[145], and thence again to the stagnum or pool originally of Nero, but afterwards retained under the Colosseum; a second to the Palatine, passing down the western side of the Clivus Scauri opposite to the church of SS. John and Paul. Then, after making one of the usual angles, it was carried across the valley on the arches attributed to Nero, but in this part really after his time, the lower portions of some of which remain. The third branch was to the Aventine. The plan for this was not carried out until the time of Trajan, when a lofty arcade was made across the valley from the Cœlian to the Aventine, passing over the Porta Capena above the Aqua Appia, which had previously been made in the same line, and with new reservoirs for it, generally by the side of the old subterranean ones. One great reservoir under the Cœlian occupies a considerable part of the space between the cliff and the present road, and is now turned into a gardener’s house. The excavations made there in 1868 have been described in the account of the Appia; the piers of the tall brick arcade of Trajan remain on both sides of the road leading direct to the north end of the ruins of the Piscina Publica, on the other side of the Marrana, under S. Balbina; the upper part of this great building is of the time of Trajan. On the side of the Cœlian are remains of another large castellum, of two stories, of the same period. There are also remains of this aqueduct on the brow of the Aventine Hill, near the church of S. Prisca, in front of the monastery, now in a vineyard opposite to the Palatine, and overlooking the Circus Maximus.

The water both of the Anio Vetus and of the Anio Novus was of inferior quality, and was used chiefly for watering gardens, and for the more common purposes in the city; the Anio Novus, being higher than any of the others, and the water very abundant, assisted all the rest. Trajan endeavoured to improve the quality of the water by excluding the more turbid sources, and using only the most pure, as we learn from Frontinus, who was the person charged with the execution of the work[146]; and this inscription was put up, IMPERATOR CAESAR NERVA TRAJANVS AVGVSTVS.

The waters of the Claudian and Anio Novus are stated by Frontinus[147] to have been united after their entrance into the city, and then distributed to all the fourteen Regiones. Several subdivisions must therefore have been made at different points, and, wherever a division or a junction took place, a castellum aquæ was required. The union of the two streams was probably made in the large reservoir at the angle of the Sessorian gardens and City wall near the Porta Maggiore. Another great division was over the Arch of Dolabella; one branch was afterwards carried on by Domitian to the Palatine upon the lofty arches, some of which still remain, and into his reservoir at the south-west corner of the Palatine Hill, part of the baths or thermæ of his palace. The branch over the Via Appia to the Piscina Publica and the Aventine was not made until the time of Trajan and Hadrian. A great deal of work was done to the aqueducts at that period. The amazement of the people at seeing copious streams of water pouring over the arid heights and slopes of the Aventine, is recorded by a contemporary author. This was the branch of which a portion remains near Santa Prisca. The branch from the Palatine to the Capitol, of which two of the tall piers remain[148], was made by Caligula; this is sometimes called a bridge across the Forum. To convey the water to the other Regiones, the older conduits or specus were probably used.