History of the Peloponnesian War

And should the attempt succeed, and Delium be fortified, they confidently hoped, that even if no change in their constitution were immediately made by the Boeotians, yet when these posts were occupied by Athenian garrisons, and the land was being plundered, and the several parties had a rallying place close at hand, that things would not remain in their present position, but that, in the course of time, when the Athenians supported the disaffected, and the power of the oligarchs was disunited, they would settle them to their own advantage. Such then was the design in preparation.

Now Hippocrates himself, with a force raised at home, was ready, when the time came, to take the field against the Boeotians; but Demosthenes he sent on before, with the forty ships mentioned, to Naupactus; that after raising in those quarters an army of Acamanians and the other allies, he might sail to Siphae, in expectation of its being betrayed to him: and the day had been fixed between them on which they were simultaneously to carry out these plans.

Accordingly, Demosthenes went to Naupactus, and finding $Aeniadae compelled by all the Acarnanians to join the Athenian confederacy, and having himself raised all the allies on that side, and marched first against Salynthius and the Agraeans, and reduced them to subjection, he proceeded to make his other preparations for going at the proper time to Siphae.