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.
The Athenians under Diphilus now sailed out against them with thirty-three ships from Naupactus,
and the Corinthians, at first not moving, at length thought they saw their opportunity, raised the signal, and advanced and engaged the Athenians.