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.
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.