northern Italy, produced in the following year (554) a general insurrection spreading beyond the two tribes immediately threatened, the Boii and Insubres.  The Ligurians were driven to arms by the nearer approach of the danger, and even the youth of the Cenomani on this occasion listened less to the voice of their cautious chiefs than to the urgent appeal of their kinsmen who were in peril.  Of “the two barriers against the raids of the Gauls,” Placentia and Cremona, the former was sacked—­not more than 2000 of the inhabitants of Placentia saved their lives—­and the second was invested.  In haste the legions advanced to save what they could.  A great battle took place before Cremona.  The dexterous management and the professional skill of the Phoenician leader failed to make up for the deficiencies of his troops; the Gauls were unable to withstand the onset of the legions, and among the numerous dead who covered the field of battle was the Carthaginian officer.  The Celts, nevertheless, continued the struggle; the same Roman army which had conquered at Cremona was next year (555), chiefly through the fault of its careless leader, almost destroyed by the Insubres; and it was not till 556 that Placentia could be partially re-established.  But the league of the cantons associated for the desperate struggle suffered from intestine discord; the Boii and Insubres quarrelled, and the Cenomani not only withdrew from the national league, but purchased their pardon from the Romans by a disgraceful betrayal of their countrymen; during a battle in which the Insubres engaged the Romans on the Mincius, the Cenomani attacked in rear, and helped to destroy, their allies and comrades in arms (557).  Thus humbled and left in the lurch, the Insubres, after the fall of Comum, likewise consented to conclude a separate peace (558).  The conditions, which the Romans prescribed to the Cenomani and Insubres, were certainly harder than they had been in the habit of granting to the members of the Italian confederacy; in particular, they were careful to confirm by law the barrier of separation between Italians and Celts, and to enact that never should a member of these two Celtic tribes be capable of acquiring the citizenship of Rome.  But these Transpadane Celtic districts were allowed to retain their existence and their national constitution—­so that they formed not town-domains, but tribal cantons—­and no tribute, as it would seem, was imposed on them.  They were intended to serve as a bulwark for the Roman settlements south of the Po, and to ward off from Italy the incursions of the migratory northern tribes and the aggressions of the predatory inhabitants of the Alps, who were wont to make regular razzias in these districts.  The process of Latinizing, moreover, made rapid progress in these regions; the Celtic nationality was evidently far from able to oppose such resistance as the more civilized nations of Sabellians and Etruscans.  The celebrated Latin comic poet Statius Caecilius, who died in 586, was a manumitted Insubrian; and Polybius, who visited these districts towards the close of the sixth century, affirms, not perhaps without some exaggeration, that in that quarter only a few villages among the Alps remained Celtic.  The Veneti, on the other hand, appear to have retained their nationality longer.