Thucydides, History of the Peloponnesian War
Benjamin Jowett, Ed.

42. During the same summer and immediately afterwards the Athenians attacked the Corinthian¹ territory with eighty ships, two thousand heavy-armed, and cavalry to the number of two hundred conveyed in horse transports. They were accompanied by allies from Miletus, Andros, and Carystus. Nicias the son of Niceratus, and two others, were in command. [2] Very early in the morning they put in between the promontory Chersonesus and the stream Rhetus, to that part of the coast which is overhung by the Solygean ridge; there in ancient times Dorian invaders had taken up their position and fought against their Aeolian enemies in Corinth, and to this day there is a village, called Solygea, on the hill which they occupied. From the beach where the crews landed this village is distant nearly a mile and a-half, the city of Corinth about seven miles, and the isthmus about two miles and a quarter. [3] The Corinthians, having had early intimation from Argos of the intended invasion, came in good time to the isthmus. The whole population, with the exception of those who dwelt to the north of the isthmus and five hundred troops who were employed in protecting Ambracia and Leucadia², was on the watch to see where the Athenians would land. [4] But, having sailed in before daylight, they were not discovered; the Corinthians however were soon informed by signals of their landing; and so, leaving half their troops at Cenchreae in case the Athenians should attack Crommyon, they came to the rescue with all speed.