History of the Peloponnesian War

Against this town then Brasidas marched with his forces, starting from Arnae in Chalcidice. Having arrived about dusk at Aulon and Bromiscus, where the lake Bolbe empties itself into the sea, and there supped, he proceeded during the night. The weather was stormy, and it was snowing a little;

on which account he hurried or the more, wishing to surprise the people of Amphipolis, except those who were to betray it.

For there were residing in it some Argilians, (this people are a colony from Andros,) and some others, who were carrying on this intrigue together; some at the suggestion of Perdiccas, others at that of the Chalcidians.

But most active of all were the Argilians, who lived close by, and had always been suspected by the Athenians of forming designs upon the place. For when the opportunity now presented itself, and Brasidas had come; as they had for some time past been intriguing with their countrymen who resided there with a view to its being delivered up to him, so at that time they received him into their own town, and revolted from Athens, and took him forward that same night to the bridge over the river.

The town stands further off than the passage of the river, and the walls did not reach down to it as they do now, but there was only a small guard posted there; which Brasidas easily drove in, (partly from there being treason amongst them, and partly from the stormy weather and the suddenness of his attack,) and then crossed the bridge, and was at once master of all the property outside the town belonging to the Amphipolitans, who had houses over the whole quarter.