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.
About the same time the Camarinaeans also came to the assistance of Syracuse with five hundred heavy infantry, three hundred darters and as many archers, while the Geloans sent crews for five ships, four hundred darters and two hundred horse.
Indeed almost the whole of Sicily, except the Agrigentines, who were neutral, now ceased merely to watch events as it had hitherto done, and actively joined Syracuse against the Athenians.