History of the Peloponnesian War

[and he built it] on the Ambracian Gulf, and called it Argos after the name of his own country.

This was the largest city of Amphilochia, and had the most powerful inhabitants. But many generations afterwards, being pressed by misfortunes, they called in the Ambraciots, who bordered on Amphilochia, as joint-inhabitants; and from the Ambraciots who joined them they were taught the Greek language which they now speak, the rest of the Amphilochians being barbarians.

Now the Ambraciots in process of time drove out the Argives, and held the city by themselves.

Upon this the Amphilochians gave themselves up to the Acarnanians; and both together having called in the Athenians, who sent them Phormio for a general and thirty ships, on the arrival of Phormio they took Argos by storm, and made slaves of the Ambraciots;