itants,
and the three extensive and populous quarters of Ravenna gradually
contributed to form one of the most important cities of Italy. The
principal canal of Augustus poured a copious stream of the waters of
the Po through the midst of the city, to the entrance of the harbor; the
same waters were introduced into the profound ditches that encompassed
the walls; they were distributed by a thousand subordinate canals,
into every part of the city, which they divided into a variety of small
islands; the communication was maintained only by the use of boats and
bridges; and the houses of Ravenna, whose appearance may be compared
to that of Venice, were raised on the foundation of wooden piles.
The adjacent country, to the distance of many miles, was a deep and
impassable morass; and the artificial causeway, which connected Ravenna
with the continent, might be easily guarded or destroyed, on the
approach of a hostile army These morasses were interspersed, however,
with vineyards: and though the soil was exhausted by four or five crops,
the town enjoyed a more plentiful supply of wine than of fresh water.
[61] The air, instead of receiving the sickly, and almost pestilential,
exhalations of low and marshy grounds, was distinguished, like the
neighborhood of Alexandria, as uncommonly pure and salubrious; and this
singular advantage was ascribed to the regular tides of the Adriatic,
which swept the canals, interrupted the unwholesome stagnation of the
waters, and floated, every day, the vessels of the adjacent country into
the heart of Ravenna. The gradual retreat of the sea has left the modern
city at the distance of four miles from the Adriatic; and as early as
the fifth or sixth century of the Christian aera, the port of Augustus
was converted into pleasant orchards; and a lonely grove of pines
covered the ground where the Roman fleet once rode at anchor. [62] Even
this alteration contributed to increase the natural strength of the
place, and the shallowness of the water was a sufficient barrier against
the large ships of the enemy. This advantageous situation was fortified
by art and labor; and in the twentieth year of his age, the emperor of
the West, anxious only for his personal safety, retired to the perpetual
confinement of the walls and morasses of Ravenna. The example of
Honorius was imitated by his feeble successors, the Gothic kings,
and afterwards the Exarchs, who occupied the throne and palace of
the emperors; an