(2.58) In the same summer, Hagnon the son of Nicias, and Cleopompus the son of Cleinias, who were colleagues of Pericles in his military command, took the fleet which he had employed and sailed forthwith against the Thracian Chalcidians and against Potidaea, which still held out. On their arrival they brought engines up to the walls, and tried every means of taking the town. But they did not succeed; nor did the result by any means correspond to the magnitude of their armament; for thither too the plague came and made dreadful havoc among the Athenian troops. Even the soldiers who were previously there and had been in good health caught the infection from the forces under Hagnon. But the army of Phormio33 escaped; for he and his sixteen hundred troops had left Chalcidicè. And so Hagnon returned with his fleet to Athens, having lost by the plague out of four thousand hoplites a thousand and fifty men in about forty days. But the original armament34 remained and prosecuted the siege.