This vast country, by far the largest fertile plain in the mountainous peninsula, contained potentially its best agricultural land, and offered the Romans the opportunity to expand enormously their population and economic resources by mass colonisation.
The Romans subjugated the Gauls of the Pianura Padana in a series of hard-fought campaigns in the late 3rd century BC.
During the Carthaginian general Hannibal's invasion of Italy (218 BC–203 BC), Roman military control of the Pianura Padana was temporarily overthrown.
Many of the recently defeated tribes (such as the Insubres and the Boii) rebelled and joined forces with Hannibal in the hope of regaining their independence.
The time-tested Roman method of expansion was to build a brand new road straight through the newly conquered territory, and then establish a string of colonies, either of civilian settlers or of military veterans along its route.
[3] It was built, on elevated embankments, in part, on top of an older road system that linked the Adriatic to the Tyrrhenian Sea.
At Savignano sul Rubicone a Roman bridge survived until it was demolished as recently as World War II.
This area was, before the Roman conquest, the territory of the Gallic tribes Boii (who gave their name to the city of Bologna) and Senones.
The boundaries of the Roman VIII regio roughly corresponded to those of the modern Italian administrative region of Emilia-Romagna.