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.
But when their ships were near—the enemy, scattered here and there, two of them deserted immediately, while in others the crews were fighting one another;
and there was no order in anything they did. And when the Peloponnesians saw their confusion they arrayed only twenty ships against the Corcyraeans, and all the rest against the twelve Athenian ships, among which were the two sacred ships, the Salaminia and the Paralos.
Now the Corcyraeans, since they were attacking in disorder and with few ships at a time, were having trouble in their part of the battle; and the Athenians, fearing the enemy's superior numbers and seeing the danger of being surrounded, did not attack the whole body together nor the centre of the ships that were arrayed against them, but charged upon one of the wings and sank a single ship.