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.
Accordingly, Demosthenes went to Naupactus, and finding $Aeniadae compelled by all the Acarnanians to join the Athenian confederacy, and having himself raised all the allies on that side, and marched first against Salynthius and the Agraeans, and reduced them to subjection, he proceeded to make his other preparations for going at the proper time to Siphae.
About the same part of the summer, when Brasidas, being on his march with one thousand seven hundred heavy-armed to the Thrace-ward countries, had come to Heraclea in Trachinia; and when, on his sending before him a messenger to his partisans in Pharsalus, and requesting them to conduct himself and his army through the country, there came to Melitia, in Achaia, Panaerus, Dorus, Hippolochidas, Torylaus, and Strophacus, who was proxenus to the Chalcidians; upon that he proceeded on his march, being conducted both by other Thessalians, and especially by Niconidas of Larissa, who was a friend of Perdiccas.
For on other grounds it was not easy to pass through Thessaly without an escort, and with an armed force, especially, to pass through a neighbour's country without having obtained his consent, was regarded with suspicion by all the Greeks alike. Besides, the great mass of the Thessalians had always been on friendly terms with Athens;
so that, had not Thessaly, by the constitution of their country, been under the dominion of a few individuals, rather than in the enjoyment of civil equality, he would never have made his way; since even as it was, another party, of contrary views to those who have been named, met him on his march on the river Enipeus, and tried to stop him, telling him that he did wrong in advancing without the national consent.
But his conductors said that they would not escort him against their will, and that they were only attending him as friends, on his unexpectedly coming to them. Brasidas himself also told them that he came as a friend both to the country of the Thessalians and to themselves, and was bringing his forces against the Athenians, who were at war with his country, and not against them; nor did he know of any enmity existing between the Thessalians and the Lacedaemonians, to prevent their having access to each other's territory:
and now he would not advance against their will (for neither indeed could he); but yet he claimed not to be obstructed After hearing this, they went away; and he, without halting at all, pushed on at a rapid pace, according to the advice of his conductors, before a greater force might be collected to stop him. And so on the day of his setting out from Melitia he performed the whole distance to Pharsalus, and encamped on the river Apidanus;
thence to Phacium, and thence to Peraebia. At that point his Thessalian escort returned; but the Peraxbians, who were subject to the Thessalians, brought him to Dium, in the dominions of Perdiccas, a town of Macedonia lying under Mount Olympus, on the side of Thessaly.
In this way Brasidas stole a rapid march through Thessaly, before any one was prepared to stop him, and reached Perdiccas and Chalcidice.
For what brought the army up out of the Peloponnese, while the affairs of Athens were so prosperous, was the fear of the Thrace-ward cities which had revolted from the Athenians, and that of Perdiccas: