144 SECTIONAL ADDRESSES. 
study of them for over twenty-five years, and hope shortly to be able to 
complete the work with which I have been occupied for so long. 
For the present purpose I shall confine my attention almost entirely 
to the four aqueducts which drew their supplies from the upper valley 
of the Anio, the Anio Vetus (272-269 B.c.), Marcia (144-140 B.c.), Claudia, . 
and Anio Novus (both built by Caligula and Claudius, a.p. 38-52)—two 
of thém, as their name implies, taking their water from the river itself ; 
while the other two made use of excellent and very abundant springs 
which are for the most part conveyed to Rome by the modern Acqua 
Marcia, though a few of them still gush forth freely in pools which have 
a beautiful bluish tint (one of the springs was, indeed, known to the 
Romans as Caeruleus). These springs, indeed, as has been ascertained 
by the engineers of the modern aqueduct, come from holes in the roof of 
the original Roman headings. They rise under the rocks at the edge of 
the floor of the Anio valley, only a little way above the river-level, and 
come probably from huge reservoirs in the interior of the massif of Monte 
Autore, being supplied by percolation from a great basin about 1,500 
metres above sea-level, which is snow-clad for the greater part of the 
year. As the Roman headings lie some seven or eight metres below the 
present level of the valley, which has been much raised by floods, it 
seems useless to try to identify, as previous authors have done, the 
individual springs of which the Romans made use. 
We have seen that the Anio Vetus goes back to the early part of the 
third century B.c., and the Marcia to the middle of the second century B.c., 
but comparatively little of the original construction of either is left to us. 
Both were restored by Augustus—rivos aquarum omnium refecit, says the 
inscription on the arch by which the Marcia, Tepula, and Iulia crossed the 
Via Tiburtina (later part of the Porta Tiburtina and now the Porta S. 
Lorenzo); to him belong all the cippi of the aqueducts which were in 
existence in his day, and no one found it necessary to renew them; and’ 
he brought into use new springs for the Aqua Marcia which doubled its 
volume. 
It is curious that the next restoration works of which we have 
epigraphic evidence, which were carried out by Vespasian in a.D. 71, 
belong, not’to the two older aqueducts, but to the Aqua Claudia, which 
had at that date been interrupted for nine years, so that Claudius’ 
original work had lasted for ten years only ; and even this was not enough, 
for Titus had to restore it again ten years later, in a.p. 81, and speaks of 
it in what would appear exaggerated language as having collapsed owing 
to its age (a sola vetustate dilapsae) along the whole of its course. By 
this time, however, the Aqua Marcia had already fallen into disrepair, and 
was patched up in a.p. 79 by Titus. We have no direct evidence (except 
from the study of the remains themselves, which shows that a good deal 
of work was done by the emperors of the second century, especially 
Hadrian) of other restorations until we come to the time of Caracalla, 
who restored the Aqua Marcia in 212-213, and still further increased its 
volume by adding a new spring ;§ but we shall see that they were very 
extensive, and that they continued even after this date. 
It is more difficult to know how to explain their necessity. The 
* The history of all these repairs is derived from the inscriptions on the Porta 
§, Lorenzo and Porta Maggiore (C.1.L, vi. 1244-1246, 1256-1258). 
