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.
And from this, since it happened in a great and imperial state, there resulted many blunders, especially the Sicilian expedition,[*](For the history of this expedition, see Books vi and vii.) which was not so much an error of judgment, when we consider the enemy they went against, as of management; for those who were responsible for it, instead of taking additional measures for the proper support of the first troops which were sent out, gave themselves over to personal intrigues for the sake of gaining the popular leadership and consequently not only conducted the military operations with less rigour, but also brought about, for the first time, civil discord at home.
And yet, after they had met with disaster in Sicily, where they lost not only their army but also the greater part of their fleet, and by this time had come to be in a state of sedition at home, they neverthless held out ten years not only against the enemies they had before, but also against the Sicilians, who were now combined with them, and, besides, against most of their allies, who were now in revolt, and later on, against Cyrus son of the King, who joined the Peloponnesians and furnished them with money for their fleet; and they did not finally succumb until they had in their private quarrels fallen upon one another and been brought to ruin.
Such abundant grounds had Pericles at that time for his own forecast that Athens might quite easily have triumphed in this war over the Peloponnesians alone.
During the same summer the Lacedaemonians and their allies made an expedition with a hundred ships to the island of Zacynthus, which lies over against Elis. The Zacynthians are colonists of the Achaeans in the Peloponnesus and were in alliance with the Athenians.