History of the Peloponnesian War

Under the pressure of misfortune many generations afterwards, they called in the Ambraciots, their neighbors on the Amphilochian border, to join their colony; and it was by this union with the Ambraciots that they learnt their present Hellenic speech, the rest of the Amphilochians being barbarians.

After a time the Ambraciots expelled the Argives and held the city themselves.

Upon this the Amphilochians gave themselves over to the Acarnanians; and the two together called the Athenians, who sent them Phormio as general and thirty ships; upon whose arrival they took Argos by storm, and made slaves of the Ambraciots; and the Amphilochians and Acarnanians inhabited the town in common.

After this began the alliance between the Athenians and Acarnanians.