History of the Peloponnesian War

The Ambraciotes out of the city of Ambracia were come as far as Idomene. Idomene are two high hills, to the greater whereof came first undiscovered that night they whom Demosthenes had sent afore from the camp and seized it; but the Ambraciotes got first to the lesser and there encamped the same night.

Demosthenes, after supper, in the twilight, marched forward with the rest of the army, one half whereof himself took with him for the assault of the camp, and the other half he sent about through the mountains of Amphilochia.

And the next morning before day, he invaded the Ambraciotes whilst they were yet in their lodgings and knew not what was the matter, but thought rather that they had been some of their own company.

For Demosthenes had placed the Messenians on purpose in the foremost ranks, and commanded them to speak unto them as they went in the Doric dialect and to make the sentinels secure, especially seeing their faces could not be discerned, for it was yet night.