The first act of the Romans after the defeat of Hannibal was the re-establishment of their fortresses at Placentia, Cremona, and Mutina (Modena), the second was the construction of a great highway which connected Placentia through Mutina with the Via Flaminia at Rimini.  This was the work of the Consul Aemilius Lepidus in 187 B.C. and the road still bears his name.

It is obvious then that the command of the way from Italy into Cisalpine Gaul, or vice versa, lay in the hands of Rimini, and it is significant that the political boundary between them was here marked by a little river, the Rubicon, a few miles to the north of that city.  The command which Rimini thus held was purely political; it passed from her to Ravenna automatically whenever that entry was threatened.  Why?

The answer is very simple:  because Rimini could not easily be defended, while Ravenna was impregnable.

Ravenna stood from fifteen to eighteen miles north and east of the Aemilian Way and some thirty-one miles north and a little west of Rimini.  Its extraordinary situation was almost unique in antiquity and is only matched by one city of later times—­Venice.  It was built as Venice is literally upon the waters.  Strabo thus describes it:  “Situated in the marshes is the great Ravenna, built entirely on piles, and traversed by canals which you cross by bridges or ferry-boats.  At the full tides it is washed by a considerable quantity of sea water, as well as by the river, and thus the sewage is carried off and the air purified; in fact, the district is considered so salubrious that the (Roman) governors have selected it as a spot in which to bring up and exercise the gladiators.  It is a remarkable peculiarity of this place that, though situated in the midst of a marsh, the air is perfectly innocuous."[1]

[Footnote 1:  Strabo, v. i. 7, tells us Altinum was similarly situated.]

[Illustration:  Sketch Map or Ravenna region in more detail]

Ravenna must always have been impregnable to any save a modern army, so long as it was able to hold the road in and out and was not taken from the sea.  The one account we have of an attack upon it before the fall of the empire is given us by Appian and recounts a raid from the sea.  It is but an incident in the civil wars of Marius and Sulla when Ravenna, we learn, was occupied for the latter by Metellus his lieutenant.  In the year 82 B.C., says Appian, “Sulla overcame a detachment of his enemies near Saturnia, and Metellus sailed round toward Ravenna and took possession of the level wheat-growing country of Uritanus.”

This impregnable city, the most southern of Cisalpine Gaul, immediately commanded the pass between Cisalpine Gaul and Italy directly that pass was threatened, and to this I say was due a good half of its fame.  The rest must be equally divided between the fact that the city was impregnable, and therefore a secure refuge or point d’appui, and its situation upon the sea.