The appearance of the Carthaginian army on the Roman side of the Alps changed all at once the situation of affairs, and disconcerted the Roman plan of war. Of the two principal armies of the Romans, one had landed in Spain and was already engaged with the enemy there: it was no longer possible to recall it. The second, which was destined for Africa under the command of the consul Tiberius Sempronius, was fortunately still in Sicily: in this instance Roman delay for once proved useful. Of the two Carthaginian squadrons destined for Italy and Sicily, the first was dispersed by a storm, and some of its vessels were captured by the Syracusans near Messana; the second had endeavoured in vain to surprise Lilybaeum, and had thereafter been defeated in a naval engagement off that port. But the continuance of the enemy's squadrons in the Italian waters was so inconvenient, that the consul determined, before crossing to Africa, to occupy the small islands around Sicily, and to drive away the Carthaginian fleet operating against Italy. The summer passed away in the conquest of Melita, in the chase after the enemy's squadron, which he expected to find at the Lipari islands while it had made a descent near Vibo (Monteleone) and pillaged the Bruttian coast, and, lastly, in gaining information as to a suitable spot for landing on the coast of Africa; so that the army and fleet were still at Lilybaeum, when orders arrived from the senate that they should return with all possible speed for the defence of their homes.
In this way, while the two great Roman armies, each in itself equal in numbers to that of Hannibal, remained at a great distance from the valley of the Po, the Romans were quite unprepared for an attack in that quarter. No doubt a Roman army was there, in consequence of an insurrection that had broken out among the Celts even before the arrival of the Carthaginian army. The founding of the two Roman strongholds of Placentia and Cremona,