The history of Achaia is lost in the mists of time. The first inhabitants were the Pelasgians, during the Bronze Age, around the 22th BC century, followed by the Ionians and then the Achaeans who finally gave their name to the region.
Achaia in ancient times divided into cities, which from east to west were the following : Pellini, Aegira, Eges, Voura, Eliki, Aigio, Kyrenia, Rypes, Leontio, Farai, Olenia, Triteia, Patras and Dimi.
In 8th BC century the Achaean League appears and the cities of Achaia drove the monarchy and became democratic. This federation appeared self-sufficient and independent and began to play an important role, especially after the death of Alexander the Great. Chair of the Achaean Confederacy was the temple of Omario Zeus in Aigio.
In the spring of 146 BC cities decided war against the Romans. In the great battle Achaean army defeated and Romans tore the Achaean League, tore down the walls of cities and overthrew democracy.In 67 AD Nero gave autonomy, although the majority of the inhabitants of Achaia had accepted the Christian religion, which was taught by a disciple of Jesus Christ, St. Andrew who martyred in Patras.
After the conquest of Constantinople by the Franks (1204) Achaia became a province of feudal Crusader state of Geoffrey of Villehardouin and William Samplitti. In 1430 it was annexed to the Despotate of Morea whose leader was the last emperor of Byzantium, Constantine Palaeologus.
In 1460, the conqueror of Constantinople Mehmed II conquered Achaia and the entire county of Peloponnese. During the last years of Turkish rule, Achaia experienced economic and commercial boom. Patras and Aigio ( Vostitsa ) considered the best commercial ports, and many European ships sailed there.
Finally in Achaia took place the beginning of the Independence Revolution of 1821 and therefore its recent history is connected with the history of Greece.