two other gates came to be
exposed to the attacks of the enemy, the Aurelian[96] (which is now
named after Peter, the chief of the Apostles of Christ, since he lies
not far from there[97]) and the Transtiburtine Gate.[98] Thus the Goths
surrounded only about one-half of the wall with their army, but since
they were in no direction wholly shut off from the wall by the river,
they made attacks upon it throughout its whole extent whenever they
wished.

Now the way the Romans came to build the city-wall on both sides of the
river I shall now proceed to tell. In ancient times the Tiber used to
flow alongside the circuit-wall for a considerable distance, even at the
place where it is now enclosed. But this ground, on which the wall rises
along the stream of the river, is flat and very accessible. And opposite
this flat ground, across the Tiber, it happens that there is a great
hill[99] where all the mills of the city have been built from of old,
because much water is brought by an aqueduct to the crest of the hill,
and rushes thence down the incline with great force. For this reason the
ancient Romans[100] determined to surround the hill and the river bank
near it with a wall, so that it might never be possible for an enemy to
destroy the mills, and crossing the river, to carry on operations with
ease against the circuit-wall of the city. So they decided to span the
river at this point with a bridge, and to attach it to the wall; and by
building many houses in the district across the river they caused the
stream of the Tiber to be in the middle of the city. So much then for
this.

And the Goths dug deep trenches about all their camps, and heaped up the
earth, which they took out from them, on the inner side of the trenches,
making this bank exceedingly high, and they planted great numbers of
sharp stakes on the top, thus making all their camps in no way inferior
to fortified strongholds. And the camp in the Plain of Nero was
commanded by Marcias (for he had by now arrived from Gaul with his
followers, with whom he was encamped there), and the rest of the camps
were commanded by Vittigis with five others; for there was one commander
for each camp. So the Goths, having taken their positions in this way,
tore open all the aqueducts, so that no water at all might enter the
city from them. Now the aqueducts of Rome are fourteen in number, and
were made of baked brick by the men of old, being of such breadth and
height that it i