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.
Demosthenes on his arrival found Oeniadae already compelled by the united Acarnanians to join the Athenian confederacy, and himself raising all the allies in those countries marched against and subdued Salynthius and the Agraeans; after which he devoted himself to the preparations necessary to enable him to be at Siphae by the time appointed.
About the same time in the summer, Brasidas set out on his march for the Thracian places with seventeen hundred heavy infantry, and arriving at Heraclea in Trachis, from thence sent on a messenger to his friends at Pharsalus, to ask them to conduct himself and his army through the country. Accordingly there came to Melitia in Achaia Panaerus, Dorus, Hippolochidas, Torylaus, and Strophacus, the Chalcidian Proxenus, under whose escort he resumed his march,
being accompanied also by other Thessalians, among whom was Niconidas from Larissa, a friend of Perdiccas. It was never very easy to traverse Thessaly without an escort; and throughout all Hellas for an armed force to pass without leave through a neighbour's country, was a delicate step to take. Besides this the Thessalian people had always sympathized with the Athenians.
Indeed if instead of the customary close oligarchy there had been a constitutional government in Thessaly, he would never have been able to proceed; since even as it was, he was met on his march at the river Enipeus by certain of the opposite party who forbade his further progress, and complained of his making the attempt without the consent of the nation.
To this his escort answered that they had no intention of taking him through against their will; they were only friends in attendance on an unexpected victor. Brasidas himself added that he came as a friend to Thessaly and its inhabitants; his arms not being directed against them but against the Athenians, with whom he was at war, and that although he knew of no quarrel between the Thessalians and Lacedaemonians to prevent the two nations having access to each other's territory, he neither would nor could proceed against their wishes; he could only beg them not to stop him.