History of the Peloponnesian War

Towards the close of the same winter, Salaethus, a Lacedaemonian, was sent out in a trireme from Lacedaemon to Mitylene. Going by sea to Pyrrha, and from thence overland, he passed along the bed of a torrent, where the line of circumvallation was passable, and thus entering unperceived into Mitylene, told the magistrates that Attica would certainly be invaded, and the forty ships destined to relieve them arrive, and that he had been sent on to announce this and to superintend matters generally.

The Mitylenians upon this took courage, and laid aside the idea of treating with the Athenians; and now this winter ended, and with it ended the fourth year of the war of which Thucydides was the historian.