History of the Peloponnesian War
Thucydides
Thucydides. History of the Peloponnesian War. Crawley, Richard, translator. London and Toronto: J. M. Dent and Sons Ltd.; New York: E. P. Dutton and Co., 1914.
While the investment of Scione was in progress, Perdiccas sent a herald to the Athenian generals and made peace with the Athenians, through spite against Brasidas for the retreat from Lyncus, from which moment indeed he had begun to negotiate.
The Lacedaemonian Ischagoras was just then upon the point of starting with an army overland to join Brasidas; and Perdiccas, being now required by Nicias to give some proof of the sincerity of his reconciliation to the Athenians, and being himself no longer disposed to let the Peloponnesians into his country, put in motion his friends in Thessaly, with whose chief men he always took care to have relations, and go effectually stopped the army and its preparation that they did not even try the Thessalians.