Parker, John Henry: The archaeology of Rome (1,2): Illustrations to I. The primitive fortifications. II. The walls and gates of Rome. III. The historical constructions of walls (Oxford [u.a.], 1874)

Walls and Gates of Rome.

Plate VIII.
Porta Ardeatina, exterior and interior. This gate stands at an
angle from the Wall of Aurelian, with which it is incorporated; it
is on the old Via Ardeatina, an older road than the Via Appia.
This old road can be traced from that gate all the way to Ardea.
The construction of the gate is of the time of Nero, as fine brick-
work as any in Rome. This is a clear proof that there were gates
in the old mcenia or outer earth-works long before the time of
Aurelian. The theory of the local antiquaries is, that there were
no outer walls and no gates on the outer line until the time of
Aurelian, or the end of the third century. They consider the great
bank of earth on which the outer wall is evidently built as having
been made for the aqueducts only, and that the outer gates, such
as the Porta Maggiore and Porta Tiburtina, were merely arches to
carry the aqueducts over the roads. The Porta Ardeatina is evi-
dently of the first century, and has no connection with the aque-
ducts, which do not run on the walls in that part. It is, therefore,
important evidence that the theory of the Roman traditions is erro-
neous on this point. The construction of the arch on the exterior
can be clearly seen in this Photo-engraving, and any one who is
accustomed to observe these things can see at once that it is of
the time of Nero.