King Pyrrhus indeed compelled the two great cities once more--it was for the last time -- to conclude an offensive alliance; but the lukewarmness and faithlessness of that alliance, the attempts of the Carthaginians to establish themselves in Rhegium and Tarentum, and the immediate occupation of Brundisium by the Romans after the termination of the war, show clearly how much their respective interests already came into collision.
Rome and the Greek Naval Powers Rome very naturally sought to find support against Carthage from the Hellenic maritime states.

Her old and close relations of amity with Massilia continued uninterrupted.

The votive offering sent by Rome to Delphi, after the conquest of Veii, was preserved there in the treasury of the Massiliots.

After the capture of Rome by the Celts there was a collection in Massilia for the sufferers by the fire, in which the city chest took the lead; in return the Roman senate granted commercial advantages to the Massiliot merchants, and, at the celebration of the games in the Forum assigned a position of honour (-Graecostasis-) to the Massiliots by the side of the platform for the senators.

To the same category belong the treaties of commerce and amity concluded by the Romans about 448 with Rhodes and not long after with Apollonia, a considerable mercantile town on the Epirot coast, and especially the closer relation, so fraught with danger for Carthage, which immediately after the end of the Pyrrhic war sprang up between Rome and Syracuse.( 23) While the Roman power by sea was thus very far from keeping pace with the immense development of their power by land, and the war marine belonging to the Romans in particular was by no means such as from the geographical and commercial position of the city it ought to have been, yet it began gradually to emerge out of the complete nullity to which it had been reduced about the year 400; and, considering the great resources of Italy, the Phoenicians might well follow its efforts with anxious eyes.
The crisis in reference to the supremacy of the Italian waters was approaching; by land the contest was decided.