The ancient traveler and writer Paphsanias, who visited Achaia in 174 b.c., informs us: "Currently, the land between Helia and Sikyonia along the bay that extends eastward is called Achaia, because it is inhabited by the people of Achaioi, while in earlier years it was called Aigialos and those who possessed it were called Aigialeis after the king of Sikyonia, as it stands today, Aigialeas."
The Pelasgoi seem to be the first inhabitants of Aigialos and Northern Peloponnese, during the copper age, in about the 22nd century b.c.
The tribes of Pelasgoi probably came from Minor Asia and by crossing Thrace and Thessalia arrived in the area and inhabited it. The language of Pelasgoi contributed immensely to the shaping of the greek language. The so-called Protohellenes, subjugated the native populations and restructed their settlements or established new ones. It is possible that they built the following settlements: Aigialos, Paleia, Larisa, Gonoessa, Pellini, Aigeira, Aiges, Peiras, Evritias, Feloe,Rippes, Voura, Aigio, Aroe, Anthea, Messatis, Argira, Volina, Arva and others.
They called their territory Aigialia or Aigiaãlo or Aiãgialo and themselves Aigialeoi Pelasgoi. After almost seven centuries of Paelasgian domination, the area was conquered by the Ions of Attica in about 1.406 b.c.
According to the writings of Herodotus, Stravon and Paphsanias, the Ions divided the area into 12 parts and established a large village in each one of them. At that time, the area of Aigialos or Aigialeia was named Ionia with Eliki being its capital city, which was destroyed by a terrible earthquake in 373 b.c. 12 cities formed a union, among which were Aigio, Pellini, Hyperissia (formerly called Aigeira), Aiges, Voura, Farres, Triteia, Rippes, Olenos, Dymi (probably the old Paleia) and Keryneia.
The development of the area was rapid and connected to the centers of the Mycenaean Civilization and especially with Mycenae. City-settlements like Eliki, Aigio, Hyperissia, Pellini and Aigialos are also mentioned on the list of ships that took part on the Trojan War (1.193 – 1.184 b.c.), while the final decision on the first great war in the history of mankind, the blood-soaked Trojan war that lasted 10 years, was taken in Aigio at the temple Omagirios Zeus, at a meeting supervised by Agamemnon himself. Less that three hundred years passed since the Ions settled the place and they were caught in the middle of a hurricane that shook the Peloponnese. In about 1.100 b.c., the Doric tribe attempted their well-known "Invasion", crossing the Rio – Antirio passage and invading the area of Corinthos. Very soon, the Doric tribe dominated the whole of the Peloponnese, except the land of the Ions.
However, the consequent turmoil did not leave the Ions unaffected, because the Achaioi of Lakedemon and Argos who had escaped their lands took refuge in that of the Ions, which they forcefully conquered later, in about 1.088 b.c.. The dominant Achaioi, renamed the area as Achaia and secured the defense of the city-settlements that they inhabited. They transformed the old settlements into cities, each one of which included seven or eight municipalities and they founded two new cities: Patras and Leondio.
According to mythology, following the joining of the settlements of Aroe, Anthea and Messatis and on the urge of Prevgenis and his son, Patreas, Patras was established under the government of which were the market towns of Argira, Volina, Arva and, probably, the area of Voundeni where foundations of an organized city were found. Its establishment must have taken place in 1.082 b.c. or in about 1.041 b.c. Apart from Eliki which kept on being the capital city, the Achaioi maintained the two Ionian institutions, namely a governmental and a religious one: the union of the twelve cities and the amphiktyonian institution which brought together the all the inhabitants of the country to Eliki for a common sacrifice at the temple of Elikonios Poseidon.
Later, the institution of Monarchy gave its place to Democracy. In about 800 b.c. the royal house of Atreides was overturned and the Democracy of the Landowners, otherwise called the Aristocracy. At about that time, the Achaioi established the first federal organization in the history of mankind, the institution of "The Common of Achaioi" or else the so-called "The First AchaicConfederacy".
Originally, the basis for "The Common of Achaioi" was Eliki and then Aigio, where the representatives of 12 cities gathered and, following sacrifices to the gods, they conferred and "…overcame their mutual conflicts and regulated their common interests…". In fact, the wisdom and stability of "The Common of Achaioi" rendered the institution exemplary in the minds of the Greeks as well as of the foreigners. Even the Romans expressed their interest and "in the 5th century b.c. the Roman Senate sent ambassadors to Eliki to get the model of democratic federation ofthe cities…".
