Under Augustus, 15 B.C., the relations conquered territory was formed into an imperial with the province, Gallia Belgica, and the frontier line, the Romans.
The branch of the Franks - who were a confederacy, not a people - which gradually overspread Gallia Belgica, bore the name of the Salian Franks..
In the division of the provinces, Gaul fell to Antony, who entrusted Pollio with the administration of Gallia Transpadana.
It was adopted by Augustus as the boundary of Gallia Cispadana; the far-famed Rubicon was a trifling stream a few miles farther north, now called Fiumicino.
The eighth region, termed Gallia Cispadana, comprised the southern portion of Cisalpine Gaul, and was bounded on the north (as its name implied) by the river Padus or P0, from above Placentia to its mouth.