The Histories (1.10)

Thus were the Mamertines first deprived of support [*] from Rhegium, and then subjected, from causes which I have just stated, to a complete defeat on their own account. Thereupon some of them betook themselves to the protection of the Carthaginians, and were for putting themselves and their citadel into their hands; while others set about sending an embassy to Rome to offer a surrender of their city, and to beg assistance on the ground of the ties of race which united them. The Romans were long in doubt. The inconsistency of sending such aid seemed manifest. A little while ago they had put some of their own citizens to death, with the extreme penalties of the law, for having broken faith with the people of Rhegium: and now so soon afterwards to assist the Mamertines, who had done precisely the same to Messene as well as Rhegium, involved a breach of equity very hard to justify. [*] But while fully alive to these points, they yet saw that Carthaginian aggrandisement was not confined to Libya, but had embraced many districts in Iberia as well; and that Carthage was, besides, mistress of all the islands in the Sardinian and Tyrrhenian seas: they were beginning, therefore, to be exceedingly anxious lest, if the Carthaginians became masters of Sicily also, they should find them very dangerous and formidable neighbours, surrounding them as they would on every side, and occupying a position which commanded all the coasts of Italy. Now it was clear that, if the Mamertines did not obtain the assistance they asked for, the Carthaginians would very soon reduce Sicily. For should they avail themselves of the voluntary offer of Messene and become masters of it, they were certain before long to crush Syracuse also, since they were already lords of nearly the whole of the rest of Sicily. The Romans saw all this, and felt that it was absolutely necessary not to let Messene slip, or allow the Carthaginians to secure what would be like a bridge to enable them to cross into Italy.