History of the Peloponnesian War

But they neither succeeded in capturing the city, nor in their other measures, to any extent worthy of their preparations: for the plague attacked them, and this indeed utterly overpowered them there, wasting their force to such a degree, that even the soldiers of the Athenians who were there before were infected with it by the troops which came with Hagnon, though previously they had been in good health. Phormio, however, and his sixteen hundred, were no longer in the neighbourhood of the Chalcidians [and so escaped its ravages].

Hagnon therefore returned with his ships to Athens, having lost by the plague fifteen hundred out of four thousand heavy-armed, in about forty days. The soldiers who were there before still remained in the country, and continued the siege of Potidaea.

After the second invasion of the Lacedaemonians, the Athenians, when their land had been again ravaged, and the disease and the war were afflicting them at the same time, changed their views, and found fault with Pericles, thinking that he had persuaded them to go to war, and that it was through him that they had met with their misfortunes;

and they were eager to come to terms with the Lacedaemonians. Indeed they sent ambassadors to them, but did not succeed in their object. And their minds being on all sides reduced to despair, they were violent against Pericles.