History of the Peloponnesian War

The Ambraciots from the city arrived at Idomene. This town consists of two high hills; the greater of which, after night had come on, the troops sent forward from the camp by Demosthenes preoccupied unobserved; while the Ambraciots had previously ascended the smaller, and bivouaeked on it. Demosthenes, after supper, marched with the rest of the army as soon as it was evening;

himself with half of his force making for the pass, the remainder proceeding over the mountains of Amphilochia.

At dawn of day he fell upon the Ambraciots, while they were yet in their beds, and had had no notice of his measures, but much rather imagined that his forces were their own countrymen.

For Demosthenes had purposely posted the Messenians first, with orders to address them, speaking in the Doric dialect, and so creating confidence in the sentinels; while at the same time they were not visible to the eye, as it was still night.