“This city (says he) between the marshes, the sea, and the Po is only accessible on one side.  Situated beside the Ionian Sea it is surrounded and almost submerged by lagoons.  On the east is the sea, on the west it is defended by marshes across which there remains a narrow passage, a kind of gate.  The city is encircled on the north by a branch of the Po, called the Fossa Asconis, and on the south by the Po itself, which is called the Eridanus, and which is there known as the King of Rivers.  Augustus deepened its bed and made it larger; it flowed quite through the city, and its mouth formed an excellent port where once, as Dion reports [this passage of Dion Cassius is lost], a fleet of 250 ships could be stationed in all security....  The city has three names with which she glorifies herself and she is divided into three parts to which they correspond; the first is Ravenna, the last Classis, that in the midst is Caesarea between Ravenna and the sea.  Built on a sandy soil this quarter is easily approached and is commodiously situated for trade and transport.”

We thus have a picture of Ravenna as a triune city, consisting of Ravenna proper, the port Classis, and the long suburb between them, Caesarea, connected by a great causeway and everywhere watered by canals, the greatest of which was the Fossa Augusta by which a part of the waters of the Po were carried to Ravenna and thence to Classis and the sea; a city very much, we may suppose, what we know Venice to be, if we think of her in connection with the Riva, the great suburb of the Marina, and the Porto di Lido.  At Classis we must understand there was room for a fleet of two hundred and fifty ships and accommodation for arsenals, magazines, barracks, and so forth, while there is one other thing we know of this port, and that from Pliny,[1] who tells us that it had a Pharos like the famous one of Alexandria.  “There is another building (says he) that is highly celebrated, the tower that was built by a king of Egypt on the island of Pharos at the entrance to the harbour of Alexandria....  At present there are similar fires lighted up in numerous places, Ostia and Ravenna for example.  The only danger is that when these fires are thus kept burning without intermission they may be mistaken for stars.”

[Footnote 1:  Pliny xxx. vi. 18]

Such was the splendour of Ravenna in the time of Augustus.  His achievement so far as Ravenna was concerned was to understand her importance not only in regard to Italy and Cisalpine Gaul, an importance already discounted by the universal peace he had established, but in regard to the sea.  He turned Ravenna into a first-class naval port and based his eastern fleet upon her; and this was so wise an act that, so long as the empire remained strong and unhampered, Ravenna appears as the great base of its sea power in the East.

In that long peace which Italy enjoyed under the empire we hear little of Ravenna.  We know Claudius built a great gate called Porta Aurea, which was only destroyed in 1582; and we know that the great sea port had one weakness, the scarcity of good water for drinking purposes.  Martial writes