History of the Peloponnesian War

But the Athenians, distressed by the plague as well as by the war, which had recently broken out and was now at its height, thought it a serious matter to make a new enemy of Lesbos, which had a fleet and power unimpaired; and so at first they would not listen to the charges, giving greater weight to the wish that they might not be true. When, however, the envoys whom they sent could not persuade the Mytilenaeans to stop their measures for political union and their preparations, they became alarmed and wished to forestall them.

So they suddenly despatched forty ships, which happened to be ready for a cruise around the Peloponnesus, under the command of Cleïppides son of Deinias and two others;