History of the Peloponnesian War

At the time when these ships were at sea about the largest number the Athenians ever had at once were on active service, though there were as many or even more at the beginning of the war.

For one hundred ships were guarding Attica, Euboea and Salamis, and another hundred were cruising off the Peloponnesus, besides those at Potidaea and in other places, so that the number in service at the same time in a single summer was all told two hundred and fifty. It was this effort, together with Potidaea, that chiefly exhausted their resources of money.