History of the Peloponnesian War
Thucydides
Thucydides. The history of the Peloponnesian War, Volume 1-2. Dale, Henry, translator. London: Heinemann and Henry G. Bohn, 1851-1852.
And Brasidas suddenly sailed down the river to Eion, with a great number of boats, on the chance of taking the point of land which runs out from the wall, and so commanding the entrance into the place: and he attempted it by land at the same time; but was beaten off in both instances:
at Amphipolis, however, he was putting every thing in readiness. Myrcinus, an Edonian town, also came over to him; Pittacus, the king of the Edonians, having been killed by the sons of Goaxis, and Brauro his own wife: and not long after, Galepsus and Oesyme, colonies of the Thasians, did the same. Perdiccas also came immediately after the capture of Amphipolis, and took part in these arrangements.