A different course was adopted with the region on the south of the Po, which the Roman senate had determined to incorporate with Italy.  The Boii, who were immediately affected by this step, defended themselves with the resolution of despair.  They even crossed the Po and made an attempt to rouse the Insubres once more to arms (560); they blockaded a consul in his camp, and he was on the point of succumbing; Placentia maintained itself with difficulty against the constant assaults of the exasperated natives.  At length the last battle was fought at Mutina; it was long and bloody, but the Romans conquered (561); and thenceforth the struggle was no longer a war, but a slave-hunt.  The Roman camp soon was the only asylum in the Boian territory; thither the better part of the still surviving population began to take refuge; and the victors were able, without much exaggeration, to report to Rome that nothing remained of the nation of the Boii but old men and children.  The nation was thus obliged to resign itself to the fate appointed for it.  The Romans demanded the cession of half the territory (563); the demand could not be refused, and even within the diminished district which was left to the Boii, they soon disappeared, and amalgamated with their conquerors.(1)

After the Romans had thus cleared the ground for themselves, the fortresses of Placentia and Cremona, whose colonists had been in great part swept away or dispersed by the troubles of the last few years, were reorganized, and new settlers were sent thither.  The new foundations were, in or near the former territory of the Senones, Potentia (near Recanati not far from Ancona:  in 570) and Pisaurum (Pesaro:  in 570), and, in the newly acquired district of the Boii, the fortresses of Bononia (565), Mutina (571), and Parma (571); the colony of Mutina had been already instituted before the war under Hannibal, but that war had interrupted the completion of the settlement.  The construction of fortresses was associated, as was always the case, with the formation of military roads.  The Flaminian way was prolonged from its northern termination at Ariminum, under the name of the Aemilian way, to Placentia (567).  Moreover, the road from Rome to Arretium or the Cassian way, which perhaps had already been long a municipal road, was taken in charge and constructed anew by the Roman community probably in 583; while in 567 the track from Arretium over the Apennines to Bononia as far as the new Aemilian road had been put in order, and furnished a shorter communication between Rome and the fortresses on the Po.  By these comprehensive measures the Apennines were practically superseded as the boundary between the Celtic and Italian territories, and were replaced by the Po.  South of the Po there henceforth prevailed mainly the urban constitution of the Italians, beyond it mainly the cantonal constitution of the Celts; and, if the district between the Apennines and the Po was still reckoned Celtic land, it was but an empty name.