History of the Peloponnesian War

And the Syracusan generals, who were already confident as to the general situation, and intended even without this help to go against Catana, trusted the fellow much too incautiously, and at once, agreeing upon a day on which they would be there, sent him back; and themselves—the Selinuntians and some others of their allies being already present—made proclamation for the whole force of the Syracusans to take the field. And when their preparations were made and the days were near on which they had agreed to come, they proceeded towards Catana and bivouacked at the River Simaethus in the territory of Leontini.

But the Athenians, when they learned of their approach, took all their own army and such of the Sicels or others as had joined them, and embarking on their ships and boats sailed under cover of night against Syracuse.

And they disembarked at daybreak at a point opposite the Olympieium, where they proposed to occupy a camping-place; but the Syracusan horsemen, who were the first to reach Catana and found there that the whole army was gone, turned about and announced this to the infantry, and all then turned back at once and hastened to bring aid to the city.