The archæology of Rome, Part 8

by John Henry Parker

“It is the lowest of all as regards the level, supplying only the Transtiberine Regio, and the places adjacent[103].”

“The manner of beginning the Alsietine aqueduct is not described in the commentaries, nor can it now be found with certainty; it begins from the Alsietine lake, and then about the Cariæ receives water from the Sabatine lake also, as the Aquarii regulate. The Alsietine gives 392 quinariæ[104].”

The lake formerly called “Lacus Alsietina,” now called Lago di Martignano, is situated on the hills on the western side of Rome, between the Via Aurelia and the Via Claudia, (not far from the old carriage-road from Florence to Rome). It is about 679 ft. above the level of the sea; and as Rome is only 204 ft. at the Porta Maggiore, the lake is 475 ft. above the level of Rome at that high point. There is another small lake about a quarter of a mile from, and a little above the level of, the Alsietina, called Strachia Capra, which has recently been drained by a tunnel in imitation of the emissario from the lake of Albano. The water in the Lacus Alsietina has also been very much lowered in the same manner[105]. In consequence of this reducing of the level of the water, the specus of the aqueducts are now brought to view, being on the bank and above the present level of the water, so that they can distinctly be seen and entered into[106].

To begin with the highest, the specus of the Aqua Paola begins in the upper lake, and forms a junction with the water from the Alsietina Lake, near the bank of the latter, at the south end of that lake. The specus of the Alsietina of Augustus is a tunnel cut in the rock[107]. The Lacus Sabatina[108] is at the elevation of about 523 ft., and therefore 156 ft. below the Alsietina. Augustus drew an additional supply of water from this lake, and this portion only of the aqueduct of Augustus was restored by Trajan. The water for this was not drawn from the lake itself, but from the springs that supply the lake on the western shore, the side most distant from Rome. Some of the work of the time of Trajan is visible there. The specus of the Alsietina has been traced to the point of junction with the Aqua Paola (this water having been restored to use by Pope Paul III., A.D. 1540), and it still supplies the district of the Trastevere. It does not appear that Trajan used the water of the Alsietina at all, but the engineers of Pope Paul evidently did so; a tunnel, or specus, from that lake having been made in the time of Pope Paul, the entrance to which remains, with the grooves for a flood-gate[109]. After the junction with the Aqua Paola, the old wells can no longer be traced; their place is supplied by the constructions called respirators, each of which is a small square structure surmounted by a pyramid. These are evidently built over the wells, and very rudely constructed of the stone of the country, worked rough. When we arrive at the Osteria Nuova,—which is near the site of the ancient city of Cariæ[110], mentioned by Frontinus, and the old village of S. Maria in Celsano, the point of junction of the Alsietina and Sabatina,—there are evident marks of another junction of aqueducts there. The house itself, now used as an osteria or hostelry (auberge), is made out of an ancient Castellum Aquæ, as is frequently the case with similar houses in the country round Rome, and sometimes even within the walls. At about half a mile from this osteria, in a hollow, is a white house called Casale Bianco; and close to this is a fountain, supplied by a spring which runs into a specus. This water, being one of the sources of the Aqua Paola, passes through the hill at a considerable depth. At about half the distance between this and the osteria is a remarkable passage for the Aquarii into the tunnel by a very steep descent, passing sideways across the specus of the Aqua Paola, and going on to a much greater depth to the Aqua Alsietina[111]. This passage is 150 ft. in length from the surface of the hill, and 70 ft. in perpendicular depth, with ninety steps, of which only a few at the top are visible; the others are covered with earth. The water still runs through the upper specus, and is still in use, but not through the lower one[112].

From the valley beneath the sloping passage for the Aquarii, near the Osteria Nuova, Nibby[113] traced the Alsietina as a tunnel cut in the tufa rock, a part of which he saw near an oil mill. The specus then followed the low ground from the tenements of S. Niccola, Porcareccina, Maglianella, and from the Villa Panfili, to the principal gate of the monastery of S. Cosimato (or SS. Cosmas and Damian in the Trastevere), where it is stated by Cassio[114] that the specus was found in 1720, about thirty feet underground. The Naumachia of Augustus is said to have been near this monastery.

The complaints of Frontinus appear to have been listened to by the Emperor, and great changes and improvements were made in this aqueduct under his direction, in the time of Trajan; this is in fact the same as the Aqua Trajana (see X.), and the water still comes from the Lacus Sabatina, but not from the Alsietina. In going from Rome, the respirators can be followed across Monte Mario, and near the high road that passes over Ponte Molli, to the point of junction about ten miles on the road to the Cariæ [now Osteria Nuova]. Here the respirators cease; but their place is supplied by a line of old wells descending into the subterranean specus, which follows the line of the old road. This is not always the same as the new one. The other branch, which supplied the Naumachia, was the only one made in the time of Augustus. Paul V. repaired this aqueduct along the whole line, restored it to use, and put up in various places inscriptions recording this, in which he calls it the Aqua Alsietina[115]. The last of these is on his fountain at the mouth of the aqueduct, where the water still gushes out in great abundance, as it did in the sixth century, when it was observed by Procopius; this is on the Janiculum, above S. Pietro in Montorio, the highest ground in Rome.

VIII., IX. The Claudia and Anio Novus (A.D. 52).

“Afterwards Caius Cæsar, (Caligula,) who succeeded Tiberius, considered seven aqueducts scarcely sufficient for public purposes and private amusements, and began two new aqueducts in the second year of his rule as Emperor, when Aquilius Julianus and P. Nonius Asprenas were consuls (i.e. A.D. 38), in the year of Rome 789, which work Claudius in a most splendid manner finished and dedicated, on the calends of August, in the year of the city 803 (i.e. A.D. 52), when Sulla and Titianus were consuls[116].