The parties in the city were almost equally balanced. At length the ascendency remained with the national party - a result, that was due partly to the justifiable predilection which led them, if they must yield to a master at all, to prefer a Greek to a barbarian, but partly also to the dread of the demagogues that Rome, notwithstanding the moderation now forced upon it by circumstances, would not neglect on a fitting opportunity to exact vengeance for the outrages perpetrated by the Tarentine rabble. The city, accordingly, came to terms with Pyrrhus. He obtained the supreme command of the troops of the Tarentines and of the other Italians in arms against Rome, along with the right of keeping a garrison in Tarentum. The expenses of the war were, of course, to be borne by the city.  Pyrrhus, on the other hand, promised to remain no longer in Italy than was necessary; probably with the tacit reservation that his own judgment should fix the time during which he would be needed there. Nevertheless, the prey had almost slipped out of his hands. While the Tarentine envoys - the chiefs, no doubt, of the war party - were absent in Epirus, the state of feeling in the city, now hard pressed by the Romans, underwent a change. The chief command was already entrusted to Agis, a man favourable to Rome, when the return of the envoys with the concluded treaty, accompanied by Cineas the confidential minister of Pyrrhus, again brought the war party to the helm.

A firmer hand now grasped the reins, and put an end to the pitiful vacillation. In the autumn of 473 Milo, the general of Pyrrhus, landed with 3000 Epirots and occupied the citadel of the town. He was followed in the beginning of the year 474 by the king himself, who landed after a stormy passage in which many lives were lost. He transported to Tarentum a respectable but miscellaneous army, consisting partly of the household troops, Molossians, Thesprotians, Chaonians, and Ambraciots; partly of the Macedonian infantry and the Thessalian cavalry, which Ptolemy king of Macedonia had conformably to stipulation handed over to him; partly of Aetolian, Acarnanian, and Athamanian mercenaries. Altogether it numbered 20,000 phalangitae, 2000 archers, 500 slingers, 3000 cavalry, and 20 elephants, and thus was not much smaller than the army with which fifty years before Alexander had crossed the Hellespont

The affairs of the coalition were in no very favourable state when the king arrived. The Roman consul indeed, as soon as he saw the soldiers of Milo taking the field against him instead of the Tarentine militia, had abandoned the attack on Tarentum and retreated to Apulia; but, with the exception of the territory of Tarentum, the Romans virtually ruled all Italy. The coalition had no army in the field anywhere in Lower Italy; and in Upper Italy the Etruscans, who alone were still in arms, had in the last campaign (473) met with nothing but defeat. The allies had, before the king embarked, committed to him the chief command of all their troops, and declared that they were able to place in the field an army of 350,000 infantry and 20,000 cavalry. The reality formed a sad contrast to these great promises.  The army, whose chief command had been committed to Pyrrhus, had still to be created; and for the time being the main resources available for forming it were those of Tarentum alone. The king gave orders for the enlisting of an army of Italian mercenaries with Tarentine money, and called out the able-bodied citizens to serve in the war. But the Tarentines had not so understood the agreement. They had thought to purchase victory, like any other commodity, with money; it was a sort of breach of contract, that the king should compel them to fight for it themselves. The more glad the citizens had been at first after Milo's arrival to be quit of the burdensome service of mounting guard, the more unwillingly they now rallied to the standards of the king: it was necessary to threaten the negligent with the penalty of death. This result now justified the peace party in the eyes of all, and communications were entered into, or at any rate appeared to have been entered into, even with Rome. Pyrrhus, prepared for such opposition, immediately treated Tarentum as a conquered city; soldiers were quartered in the houses, the assemblies of the people and the numerous clubs (sussitia) were suspended, the theatre was shut, the promenades were closed, and the gates were occupied with Epirot guards. A number of the leading men were sent over the sea as hostages; others escaped the like fate by flight to Rome. These strict measures were necessary, for it was absolutely impossible in any sense to rely upon the Tarentines. It was only now that the king, in possession of that important city as a basis, could begin operations in the field.

The Romans too were well aware of the conflict which awaited them. In order first of all to secure the fidelity of their allies or, in other words, of their subjects, the towns that could not be depended on were garrisoned, and the leaders of the party of independence, where it seemed needful, were arrested or executed: such was the case with a number of the members of the senate of Praeneste. For the war itself great exertions were made; a war contribution was levied; the full contingent was called forth from all their subjects and allies; even the proletarians who were properly exempt from obligation of service were called to arms. A Roman army remained as a reserve in the capital. A second advanced under the consul Tiberius Coruncanius into Etruria, and dispersed the forces of Volci and Volsinii. The main force was of course destined for Lower Italy; its departure was hastened as much as possible, in order to reach Pyrrhus while still in the territory of Tarentum, and to prevent him and his forces from forming a junction with the Samnites and other south Italian levies that were in arms against Rome. The Roman garrisons, that were placed in the Greek towns of Lower Italy, were intended temporarily to check the king's progress. But the mutiny of the troops stationed in Rhegium - one of the legions levied from the Campanian subjects of Rome under a Campanian captain Decius - deprived the Romans of that important town.  It was not, however, transferred to the hands of Pyrrhus. While on the one hand the national hatred of the Campanians against the Romans undoubtedly contributed to produce this military insurrection, it was impossible on the other hand that Pyrrhus, who had crossed the sea to shield and protect the Hellenes, could receive as his allies troops who had put to death their Rhegine hosts in their own houses. Thus they remained isolated, in close league with their kinsmen and comrades in crime, the Mamertines, that is, the Campanian mercenaries of Agathocles, who had by similar means gained possession of Messana on the opposite side of the straits; and they pillaged and laid waste for their own behoof the adjacent Greek towns, such as Croton, where they put to death the Roman garrison, and Caulonia, which they destroyed.  On the other hand the Romans succeeded, by means of a weak corps which advanced along the Lucanian frontier and of the garrison of Venusia, in preventing the Lucanians and Samnites from uniting with Pyrrhus; while the main force - four legions as it would appear, and so, with a corresponding number of allied troops, at least 50,000 strong - marched against Pyrrhus, under the consul Publius Laevinus.