The interests of the agricultural class did not extend beyond Italy; the late wars had provided plenty of land for distribution, and if more were wanted it could be found in the territory of the Celts on the Po, the southern portion of which had been conquered as early as 282 but not yet divided. The interests of the urban elements, the capitalists, on the contrary, extended beyond the sea. To them the most pressing business of the moment was to vindicate the preponderance of the state to the outside world, to adjust their relations abroad as best suited their own interests, and to deliver Italy from foreign competition, and, above all, from Carthage; and not a few of the great ruling families were allured, like the Claudii, by the tempting prospect.
Carthage and Rome had come dangerously near together during the last few decades. As long before as the year 306 the two had concluded a compact by which Rome was not to intervene in Sicily nor Carthage in Italy. The rival states had indeed united against Pyrrhus, but without ever laying aside their mutual distrust; each feared that the other might effect a lodgment within its sphere of influence. And now, in the year 264, the Oscan community of the Mamertines in Messana (whilom mercenaries of Agathocles, who had exterminated the Greek inhabitants of the city) appealed to both Carthage and Rome for aid against Hiero, the ruler of Syracuse.
Rome was thus brought face to face with the most momentous decision in her whole history. The Romans were not untroubled by moral scruples nor blind to the fact that to accede to the petition would necessarily lead to war with Carthage, since Carthage had promptly taken the city under her protection and occupied it with her troops; but the opportunity was too tempting, and if it were allowed to pass, the whole of the rich island would undoubtedly fall under the sovereignty of Carthage for evermore, and her power, formidable already, would be correspondingly increased. The senate hesitated, but the consul Appius Claudius brought the matter before the comitia centuriata, and they decided in favour of rendering assistance, and thereby in favour of war.
It was a step that could never be retraced, a step of the same incalculable consequence to Rome as the occupation of Silesia was to Prussia, or the war with Spain and the occupation of Cuba and the Philippines to the United States of America. Its immediate consequences were a struggle of twenty-four years’ duration with Carthage for the possession of Sicily, and the creation of a Roman sea power which was not merely a match for that of Carthage, but actually annihilated it; its ultimate result was the acquisition of a dominion beyond sea in which Rome for the first time bore rule over tributary subjects governed by Roman magnates and exploited by Italian capitalists. A further consequence was that the Romans took advantage of the difficulties in which Carthage was involved by a mutiny of mercenaries in 237 to wrest Sardinia and Corsica from her and at the same time once more exact a huge indemnity.