Aratus (16.3-16.4)

Chares the Athenian, having been successful in a battle with the king’s generals, wrote to the people of Athens that he had won a battle which was sister to that at Marathon; and this enterprise of Aratus may be rightly called a sister of those of Pelopidas the Theban and Thrasybulus the Athenian, in which they slew tyrants, except that it surpassed them in being undertaken, not against Greeks, but against a foreign and alien power.

For the Isthmus of Corinth, forming a barrier between the seas, brings together the two regions, and thus unites our continent; and when Acrocorinthus, which is a lofty hill springing up at this centre of Greece, is held by a garrison, it hinders and cuts off all the country south of the Isthmus from intercourse, transits, and the carrying on of military expeditions by land and sea,