History of the Peloponnesian War

Meanwhile the troops from the city of Ambracia arrived at Idomene. Now it consists of two lofty hills, and of these the higher had already been seized unobserved during the night by the troops which Demosthenes had sent forward from his main army; but the lower had previously, as it chanced, been ascended by the Ambraciots, who spent the night there.

After dinner Demosthenes and the rest of the army set out immediately after nightfall, he himself with half of them making for the pass, while the rest took the road through the Amphilochian mountains.