Thucydides. History of the Peloponnesian War, 5.84: "[The Melians] at first remained neutral and took no part in the struggle, but afterwards upon the Athenians using violence and plundering their territory, assumed an attitude of open hostility."
Thucydides. History of the Peloponnesian War, 6.8: "Early in the spring of the following summer the Athenian envoys arrived from Sicily, and the Egestaeans with them, bringing sixty talents of uncoined silver, as a month's pay for sixty ships, which they were to ask to have sent them."