all above the Portella, that they are more flatly faced on the
outside, and that here and there a little mortar is used. Above all,
however, there is in the wall on one of the stones under the house no.
24, Via della Fontana an inscription,[40] which Richter, Dressel, and
Dessau all think was there when the stone was put in the wall, and
incline to allow no very remote date for the building of the wall at
that point. To me, after a comparative study of this wall and the one at
Norba, the two seem to date from very nearly the same time, and no one
now dares attribute great antiquity to the walls of Norba. But the rest
of the cyclopean wall of Praeneste is very ancient, certainly a century,
perhaps two or three centuries, older than the part from the Portella
down.

There remains still to be discussed the lower wall of the city on the
south, and a restraining terrace wall along part of the present Corso
Pierluigi. The stretch of city wall from the Porta del Sole clear across
the south front to the Porta di S. Martino is of opus quadratum, with
the exception of a stretch of opus incertum[41] below and east of the
Barberini gardens, and a small space where the city sewage has destroyed
all vestige of a wall. The restraining wall just mentioned is also of
opus quadratum and is to be found along the south side of the Corso, but
can be seen only from the winecellars on the terrace below that street.
These walls of opus quadratum were built with a purpose, to be sure, but
their entire meaning has not been understood.[42]

The upper wall, the one along the Corso, can not be traced farther than
the Piazza Garibaldi, in front of the Cathedral. It has been a mistake
to consider this a high wall. It was built simply to level up with the
Corso terrace, partly to give more space on the terrace, partly to make
room for a road which ran across the city here between two gates no
longer in existence. But more especially was it built to be the lower
support for a gigantic water reservoir which extends under nearly the
whole width of this terrace from about Corso Pierluigi No. 88 almost to
the Cathedral.[43] The four sides of this great reservoir are also of
opus quadratum laid header and stretcher.

The lower wall, the real town wall, is a wall only in appearance, for it
has but one thickness of blocks, set header and stretcher in a mass of
solid concrete.[44] This wall makes very clear the impregnability of
even the lower part of Praene