a small river flowing into the Tiber on its left bank, just below the walls of Rome. Ovid calls it “cursu brevissimus Almo” (Met.
14.329), from which it is probable that he regarded the stream that rises from a copious source under an artificial grotto at a spot called La Caffarella
as the true Almo.
This stream is, however, joined by others that furnish a much larger supply of water, one of the most considerable of which, called the Marrana degli Orti,
flows from the source near Marino
that was the ancient Aqua Ferentina, another is commonly known as the Acqua Santa.
The grotto and source already mentioned were long regarded, but certainly without foundation, as those of Egeria, and the Vallis Egeriae was supposed to. be the Valle della Caffarella,
through which the Almo flows.
The grotto itself appears to have been constructed in imperial times: it contains a marble figure, much mutilated, which is probably that of the tutelary deity of the stream, or the god Almo. (Nardini, Roma Antica,
vol. i. pp. 157--161, with [p. 1.106]
Nibby's notes; Nibby, Dintorni di Roma,
; vol. i. p. 130; Gell, Top. of Rome,
p. 48; Burgess, Antiquities of Rome,
vol. i. p. 107.) From this spot, which is about half a mile from the church of S. Sebastiano,
and two miles from the gates of Rome, the Almo has a course of between 3 and 4 miles to its confluence with the Tiber, crossing on the way both the Via Appia and the Via Ostiensis.
It was at the spot where it joins the Tiber that the celebrated statue of Cybele was landed, when it was brought from Pessinus in Phrygia to Rome in B.C. 204; and in memory of this circumstance the singular ceremony was observed of washing the image of the goddess herself, as well as her sacred implements, in the waters of the Almo, on a certain day (6 Kal. Apr., or the 27th of March) in every year: a superstition which subsisted down to the final extinction of paganism. (Ov. Fast. 4.337
-340; Lucan 1.600
; Martial. 3.47. 2; Stat. Silv. 5.1. 222
; Sil. Ital. 8.365
; Amm. Marc. 23.3.7
The little stream appears to have retained the name of Almo as late as the seventh century: it is now commonly called the Acquataccia,
a name which is supposed by some to be a corruption of Acqua d'Appia,
from its crossing the Via Appia.
The spot where it is traversed by that road was about 1« mile from the ancient Porta Capena; but the first region of the city, according to the arrangement of Augustus, was extended to the very bank of the Almo. (Preller, Die Regionen Roms,