There could be no doubt of the policy of the Aetolians. They were ashamed indeed to attack the Achaeans openly, because they could not ignore their recent obligations to them in the war with Demetrius: but they were plotting with the Lacedaemonians; and showed their jealousy of the Achaeans by not only conniving at the treacherous attack of Cleomenes upon Tegea, Mantinea, and Orchomenus (cities not only in alliance with them, but actually members of their league), but by confirming his occupation of those places. In old times they had thought almost any excuse good enough to justify an appeal to arms against those who, after all, had done them no wrong: yet they now allowed themselves to be treated with such treachery, and submitted without remonstrance to the loss of the most important towns, solely with the view of creating in Cleomenes a formidable antagonist to the Achaeans. These facts were not lost upon Aratus and the other officers of the league: and they resolved that, without taking the initiative in going to war with any one, they would resist the attempts of the Lacedaemonians. Such was their determination, and for a time they persisted in it: but immediately afterwards Cleomenes began to build the hostile fort in the territory of Megalopolis, called the Athenaeum, and showed an undisguised and bitter hostility. Aratus and his colleagues accordingly summoned a meeting of the league, and it was decided to proclaim war openly against Sparta.