With the decline of the Mycenaean centres, Achaians from the Argolid came and settled here, founding important cities. The region is named Achaia after them. Though politically insignificant through most of antiquity, it started to play a more dynamic role in 280 B.C., when the Achaian Confederacy was created. In 146 B.C. the area fell to the Romans.

It embraced Christianity earlier than the rest of Greece (St. Andrew the Apostle preached in Patras and was martyred there). In 1205 it occupied centre stage with the founding of the Principality of Achaia by the Franks.

Before too long it passed to the hands of the Palaiologues who ruled the Peloponnese from Mistra; the Turks succeeded them in 1460. For a short period (1687 - 1715), the area was a Venetian colony. It was liberated in 1828

The monastery of Agia Lavra, 5 km. from Kalavrita, is built at a point which commands a view of the whole Vouraikos river valley. Constructed in 961 at an altitude of 961 metres, it once also had 961 monks. It was here, from the present building dating from 1689, that the call for "Freedom or Death" first rang out in 1821, commanding Greeks to defend their heritage and throw off the Turkish oppressors.

The revolutionary banner was raised in the garden under the historic plane tree. The monastery church has a fine carved icon screen (iconostasis), frescoes damaged by fire and the icon of Agia Lavra. Apart from the revolutionary banner, the relics include a very old Gospel, a gift of Catherine the Great; gold crosses; reliquaries and a valuable collection of early Christian and ancient objects. On a hill opposite, a monument to the heroes of the Revolution of 1821 looks down over the monastery.