Already in 555-6 Attalus had requested from the Romans military aid against Antiochus, who had occupied his territory while the troops of Attalus were employed in the Roman war.

The more energetic Rhodians even declared to king Antiochus, when in the spring of 557 his fleet appeared off the coast of Asia Minor, that they would regard its passing beyond the Chelidonian islands (off the Lycian coast) as a declaration of war; and, when Antiochus did not regard the threat, they, emboldened by the accounts that had just arrived of the battle at Cynoscephalae, had immediately begun the war and had actually protected from the king the most important of the Carian cities, Caunus, Halicarnassus, and Myndus, and the island of Samos.

Most of the half-free cities had submitted to Antiochus, but some of them, more especially the important cities of Smyrna, Alexandria Troas, and Lampsacus, had, on learning the discomfiture of Philip, likewise taken courage to resist the Syrian; and their urgent entreaties were combined with those of the Rhodians.
It admits of no doubt, that Antiochus, so far as he was at all capable of forming a resolution and adhering to it, had already made up his mind not only to attach to his empire the Egyptian possessions in Asia, but also to make conquests on his own behalf in Europe and, if not to seek on that account a war with Rome, at any rate to risk it The Romans had thus every reason to comply with that request of their allies, and to interfere directly in Asia; but they showed little inclination to do so.

They not only delayed as long as the Macedonian war lasted, and gave to Attalus nothing but the protection of diplomatic intercession, which, we may add, proved in the first instance effective; but even after the victory, while they doubtless spoke as though the cities which had been in the hands of Ptolemy and Philip ought not to be taken possession of by Antiochus, and while the freedom of the Asiatic cities, Myrina, Abydus, Lampsacus,( 1) and Cius, figured in Roman documents, they took not the smallest step to give effect to it, and allowed king Antiochus to employ the favourable opportunity presented by the withdrawal of the Macedonian garrisons to introduce his own.

In fact, they even went so far as to submit to his landing in Europe in the spring of 558 and invading the Thracian Chersonese, where he occupied Sestus and Madytus and spent a considerable time in the chastisement of the Thracian barbarians and the restoration of the destroyed Lysimachia, which he had selected as his chief place of arms and as the capital of the newly-instituted satrapy of Thrace.