History of the Peloponnesian War

After Amphipolis was taken, the Athenians were brought into great fear, especially for that it was a city that yielded them much profit, both in timber which is sent them for the building of galleys and in revenue of money, and because also, though the Lacedaemonians had a passage open to come against their confederates, the Thessalians convoying them, as far as to Strymon, yet if they had not gotten that bridge, the river being upwards nothing but a vast fen, and towards Eion well guarded with their galleys, they could have gone no further; which now they thought they might easily do, and therefore feared lest their confederates should revolt.

For Brasidas both showed himself otherwise very moderate, and also gave out in speech that he was sent forth to recover the liberty of Greece.

And the cities which were subject to the Athenians, hearing of the taking of Amphipolis, and what assurance he brought with him, and of his gentleness besides, were extremely desirous of innovation, and sent messengers privily to bid him draw near, every one striving who should first revolt.