While the storm was thus gathering from far and wide against Rome, it was on this, as on all occasions, the Hellenes implicated in the enterprise, who were of the least moment, and yet took action of the greatest importance and with the utmost impatience. The exasperated and arrogant Aetolians began by degrees to persuade themselves that Philip had been vanquished by them and not by the Romans, and could not even wait till Antiochus should advance into Greece. Their policy is characteristically expressed in the reply, which their strategusgave soon afterwards to Flamininus, when he requested a copy of the declaration of war against Rome: that he would deliver it to him in person, when the Aetolian army should encamp on the Tiber. The Aetolians acted as the agents of the Syrian king in Greece and deceived both parties, by representing to the king that all the Hellenes were waiting with open arms to receive him as their true deliverer, and by telling those in Greece who were disposed to listen to them that the landing of the king was nearer than it was in reality. Thus they actually succeeded in inducing the simple obstinacy of Nabis to break loose and to rekindle in Greece the flame of war two years after Flamininus's departure, in the spring of 562; but in doing so they missed their aim. Nabis attacked Gythium, one of the towns of the free Laconians that by the last treaty had been annexed to the Achaean league, and took it; but the experienced strategus of the Achaeans, Philopoemen, defeated him at the Barbosthenian mountains, and the tyrant brought back barely a fourth part of his army to his capital, in which Philopoemen shut him up. As such a commencement was no sufficient inducement for Antiochus to come to Europe, the Aetolians resolved to possess themselves of Sparta, Chalcis, and Demetrias, and by gaining these important towns to prevail upon the king to embark. In the first place they thought to become masters of Sparta, by arranging that the Aetolian Alexamenus should march with 1000 men into the town under pretext of bringing a contingent in terms of the alliance, and should embrace the opportunity of making away with Nabis and of occupying the town. This was done, and Nabis was killed at a review of the troops; but, when the Aetolians dispersed to plunder the town, the Lacedaemonians found time to rally and slew them to the last man. The city was then induced by Philopoemen to join the Achaean league. After this laudable project of the Aetolians had thus not only deservedly failed, but had had precisely the opposite effect of uniting almost the whole Peloponnesus in the hands of the other party, it fared little better with them at Chalcis, for the Roman party there called in the citizens of Eretria and Carystus in Euboea, who were favourable to Rome, to render seasonable aid against the Aetolians and the Chalcidian exiles. On the other hand the occupation of Demetrias was successful, for the Magnetes to whom the city had been assigned were, not without reason, apprehensive that it had been promised by the Romans to Philip as a prize in return for his aid against Antiochus; several squadrons of Aetolian horse moreover managed to steal into the town under the pretext of forming an escort for Eurylochus, the recalled head of the opposition to Rome. Thus the Magnetes passed over, partly of their own accord, partly by compulsion, to the side of the Aetolians, and the latter did not fail to make use of the fact at the court of the Seleucid.

Antiochus took his resolution. A rupture with Rome, in spite of endeavours to postpone it by the diplomatic palliative of embassies, could no longer be avoided. As early as the spring of 561 Flamininus, who continued to have the decisive voice in the senate as to eastern affairs, had expressed the Roman ultimatum to the envoys of the king, Menippus and Hegesianax; viz. that he should either evacuate Europe and dispose of Asia at his pleasure, or retain Thrace and submit to the Roman protectorate over Smyrna, Lampsacus, and Alexandria Troas. These demands had been again discussed at Ephesus, the chief place of arms and fixed quarters of the king in Asia Minor, in the spring of 562, between Antiochus and the envoys of the senate, Publius Sulpicius and Publius Villius; and they had separated with the conviction on both sides thata peaceful settlement was no longer possible. Thenceforth war was resolved on in Rome. In that very summer of 562 a Roman fleet of 30 sail, with 3000 soldiers on board, under Aulus Atilius Serranus, appeared off Gythium, where their arrival accelerated the conclusion of the treaty between the Achaeans and Spartans; the eastern coasts of Sicily and Italy were strongly garrisoned, so as to be secure against any attempts at a landing; a land army was expected in Greece in the autumn. Since the spring of 562 Flamininus, by direction of the senate, had journeyed through Greece to thwart the intrigues of the opposite party, and to counteract as far as possible the evil effects of the ill-timed evacuation of the country. The Aetolians had already gone so far as formally to declare war in their diet against Rome. But Flamininus succeeded In saving Chalcis for the Romans by throwing into it a garrison of 500 Achaeans and 500 Pergamenes. He made an attempt also to recover Demetrias; and the Magnetes wavered. Though some towns in Asia Minor, which Antiochus had proposed to subdue before beginning the great war, still held out, he could now no longer delay his landing, unless he was willing to let the Romans recover all the advantages which they had surrendered two years before by withdrawing their garrisons from Greece. He collected the vessels and troops which were at hand - he had but 40 decked vessels and 10,000 infantry, along with 500 horse and 6 elephants - and started from the Thracian Chersonese for Greece, where he landed in the autumn of 562 at Pteleum on the Pagasaean gulf, and immediately occupied the adjoining Demetrias. Nearly about the same time a Roman army of some 25,000 men under the praetor Marcus Baebius landed at Apollonia. The war was thus begun on both sides.

Everything depended on the extent to which that comprehensively-planned coalition against Rome, of which Antiochus came forward as the head, might be realized. As to the plan, first of all, of stirring up enemies to the Romans in Carthage and Italy, it was the fate of Hannibal at the court of Ephesus, as through his whole career, to have projected his noble and high-spirited plans for the behoof of people pedantic and mean. Nothing was done towards their execution, except that some Carthaginian patriots were compromised; no choice was left to the Carthaginians but to show unconditional submission to Rome. The camarilla would have nothing to do with Hannibal - such a man was too inconveniently great for court cabals; and, after having tried all sorts of absurd expedients, such as accusing the general, with whose name the Romans frightened their children, of concert with the Roman envoys, they succeeded in persuading Antiochus the Great, who like all insignificant monarchs plumed himself greatly on his independence and was influenced by nothing so easily as by the fear of being ruled, into the wise belief that he ought not to allow himself to be thrown into the shade by so celebrated a man. Accordingly it was in solemn council resolved that the Phoenician should be employed in future only for subordinate enterprises and for giving advice - with the reservation, of course, that the advice should never be followed. Hannibal revenged himself on the rabble, by accepting every commission and brilliantly executing all.