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 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.
On board the ships were one thousand Lacedaemonian hoplites, and Cnemus a Spartan was admiral. And making a descent upon the land they ravaged most of it; but as the inhabitants would not come to terms they sailed back home.