The Romans certainly kept a wary eye on the Carthaginian activity in Spain, although as yet they had no direct involvement in the area. In 231 a delegation of senators went to Hamilcar to question him about the motives for his aggressive campaigns and was told that these were necessary if Carthage was to pay her indemnity to Rome. Later, sometime around 226, another set of envoys went to Hasdrubal, who formally agreed not to expand beyond the River Ebro. It is possible that Rome's interest in Spain was encouraged by her long-time ally, Massilia, but the concern over growing Carthaginian power may well have been genuine. As yet Rome had no direct connection with the Spanish Peninsula, although Latin traders were certainly active there by the second half of the third century.27
Rome's world was gradually expanding beyond the Italian Peninsula, with her newly acquired overseas provinces and the powerful navy created during the war with Carthage. In 228 and 219, Roman consuls at the head of fleets of warships fought two wars in Illyria on the other side of the Adriatic, allegedly provoked by the piracy routinely practised by the Illyrian kingdom. Nevertheless it was with an Italian problem, the Gallic tribes of northern Italy, that the Senate was most concerned between the wars. Latin colonies established on land captured from the tribes, notably Ariminum which was founded in 268, were a continual source of friction with the Gauls. Yet as Rome's population increased and her web of alliances expanded the need to find land for the poorer Roman and Latin citizens steadily grew and the fertile plains of Cisalpine Gaul proved especially attractive. In 232 one of the tribunes of the plebs, Caius Flaminius, carried a law to distribute much of the captured ager Gallicus to poorer citizens. These were not to be concentrated in new colonies, but each plot of land allocated individually to create a large number of small farms. There was much opposition to this move, in part because other senators resented the prestige that Flaminius would gain and the money that he would doubtless make in the process, but also because it was seen as a provocative gesture.28
In 238 the Boii had rallied other tribes and some warriors from beyond the Alps to attack Ariminum, but the war had fizzled out when bickering amongst the Gauls turned to open fighting and they were forced to make peace. By 225 resentment against the flood of setders sparked another, far larger war. This time the Boii united with the Insubres, and were joined by a large contingent of semi-professional warriors from Transalpine Gaul, known as the Gaesatae. When the Gallic army invaded Etruria, it is said to have mustered around 70,000 men. The Gauls were undefeated when they decided to withdraw in front of the consul Lucius Aemilius Papus' army and carry away their substantial booty. The two Roman armies were completely unaware of each other's presence and by a stroke of luck the other consul, Caius Atilius Regulus, who had been recalled from Sardinia, found himself directly blocking the Gauls' line of march. Trapped between the two Roman armies, the tribes were forced to fight at Telamon, forming up in two lines back to back in order to face the enemy armies coming on from opposite directions. Despite this disadvantage the battie was a desperate one. Regulus fell in the early stages and his severed head was carried in triumph to one of the Gallic kings, and it was only after a long struggle that the Romans prevailed, inflicting appalling casualties on the enemy.
In 224 both consuls led armies north and forced the Boii to accept peace. The next year's consuls, the same Flaminius who as tribune had passed the bill to distribute the ager Gallicus, and Publius Furius also invaded the tribal lands. Flaminius won a great victory over the Insubres and another tribe, the Cenomani, although a hostile tradition gave the credit for this victory to the army's tribunes. According to Polybius it was these officers who ordered the hastati to be re-equipped with the spears of the triarii instead of theirpila. The first line of the legions was then formed into a dense, defensive formation, standing fast until the fury and enthusiasm of the initial Gallic charge had exhausted itself. In 222 the Gauls sued for peace, but the new consuls, eager for glory or perhaps in the genuine belief that the enemy were undefeated, persuaded the Senate to reject these approaches and both took armies against them. One of the consuls, Marcus Claudius Marcellus, relieved the siege of Clastidium, fighting an action in which he single-handedly killed a Gallic King, Britomarus, and stripped him of his armour, winning the highest honour available to a Roman aristocrat, the right to dedicate the spolia opima.29 His colleague Cnaeus Cornelius Scipio stormed Mediolanum (modern Milan), the tribal capital of the Insubres. After these continued defeats, the tribes all surrendered to Rome, yielding up more of their land. In 218 two new colonies were established, one on either side of the Po at Cremona and Placentia, 6,000 settlers going to each. The provocative presence of a new wave of setders further north than before, and occupying prime land, only added to the bitterness and resentment of the defeated tribes, ensuring that peace would prove short-lived.
Spain and northern Italy would see much activity when war was finally renewed between Rome and Carthage. In addition, many of the individuals on both sides who were prominent in the campaigns in the 220s would later play a significant role in the Hannibalic war. For the generation of Roman commanders who grew up between the wars with Carthage, their military experiences in Sardinia, Illyria and, most of all, Cisalpine Gaul accustomed them to warfare against armies which were tactically unsophisticated, however individually brave and skilled the warriors composing them might have been. It was to prove poor preparation for confronting a general as skilled as Hannibal at the head of a well-trained army.