have run, following the course of the river, from near Forli, where
there still remains a village called S. Maria in Acquedotto, to
Ravenna.

[Illustration: GREEK RELIEF FROM A TEMPLE OF NEPTUNE]

The great city-port thus became one of the most important and
considerable of the cities of Italy, at a time when the whole of the
West was rapidly increasing in wealth and population, and especially
the old province of Cisapline Gaul, which had indeed become, during
the _pax romana_, the richest part of the new Italy. Always an
important military port it was often occupied by the emperors as their
headquarters from which to watch and to oppose the advance of their
enemies into Italy, and the possessor of it, for the reasons I have
set forth, was always in a commanding position. Thus in A.D. 193 it
was the surrender of Ravenna without resistance that gave the empire
to Septimius Severus, when, scarcely allowing himself time for sleep
or food, marching on foot and in complete armour, he crossed the Alps
at the head of his columns to punish the wretched Didius Julianus and
to avenge Pertinax. It was there in 238 that Pupienus was busy
assembling his army to oppose Maximin when he received the news of the
death of his enemy before Aquileia.

And because it was impregnable and secluded it was often chosen too as
a place of imprisonment for important prisoners.

It is true that we know very little, in detail, of the life of any
city other than Rome during those years of the great Peace in which we
see the empire change from a Pagan to a Christian state. Those
centuries which saw Christendom slowly emerge, in which Europe was