History of the Peloponnesian War
Thucydides
Thucydides, Vol. 1-4. Smith, Charles Foster, translator. London and Cambridge, MA: Heinemann and Harvard University Press, 1919-1923.
After taking up the dead the Athenians sailed back home, but Clearidas and his followers remained and set in order the affairs of Amphipolis.
About the same time, towards the close of this summer, Rhamphias, Autocharidas, and Epicydidas, who were Lacedaemonians, were on their way with reinforcements, consisting of nine hundred hoplites, to the strongholds in Thrace, and arriving at Heracleia in Trachis they set in order whatever seemed to them amiss.