But after various attempts to induce Nabis to yield, and particularly to give up the city of Argos belonging to the Achaean league, which Philip had surrendered to him, no course at last was left to Flamininus but to have war declared against the obstinate petty robber-chieftain, who reckoned on the well-known grudge of the Aetolians against the Romans and on the advance of Antiochus into Europe, and pertinaciously refused to restore Argos.

War was declared, accordingly, by all the Hellenes at a great diet in Corinth, and Flamininus advanced into the Peloponnesus accompanied by the fleet and the Romano-allied army, which included a contingent sent by Philip and a division of Lacedaemonian emigrants under Agesipolis, the legitimate king of Sparta (559).

In order to crush his antagonist immediately by an overwhelming superiority of force, no less than 50,000 men were brought into the field, and, the other towns being disregarded, the capital itself was at once invested; but the desired result was not attained.

Nabis had sent into the field a considerable army amounting to 15,000 men, of whom 5000 were mercenaries, and he had confirmed his rule afresh by a complete reign of terror--by the execution -en masse- of the officers and inhabitants of the country whom he suspected.

Even when he himself after the first successes of the Roman army and fleet resolved to yield and to accept the comparatively favourable terms of peace proposed by Flamininus, "the people," that is to say the gang of robbers whom Nabis had domiciled in Sparta, not without reason apprehensive of a reckoning after the victory, and deceived by an accompaniment of lies as to the nature of the terms of peace and as to the advance of the Aetolians and Asiatics, rejected the peace offered by the Roman general, so that the struggle began anew.