History of the Peloponnesian War

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.

When therefore he fell upon them, they routed them, and slew the greater part on the spot; the rest rushed in flight over the mountains.