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.
Returning thence to Rhegium, they found that Pythodorus son of Isolochus, an Athenian general, had come to succeed Laches in command of the fleet.
For their allies in Sicily had sailed to Athens and persuaded them to aid them with a larger fleet; for though their territory was dominated by the Syracusans, yet since they were kept from the sea by only a few ships they were collecting a fleet and making preparations with the determination not to submit.
And the Athenians manned forty ships to send to them, partly because they believed that the war in Sicily could sooner be brought to an end in this way, and partly because they wished to give practice to their fleet.
Accordingly they despatched one of their generals, Pythodorus, with a few ships, and were planning later on to send Sophocles son of Sostratidas and Eurymedon son of Thucles with the main body of the fleet.