The Ancient Dymi was located in the position of K.Achaia in nowadays. This issue has been found out and certified from the archaelogical researches. The ancient writers and specifically the Byzantines give confused information. As a result, the aspect that Olenos was placed in K.Achaia has been dominated for many centuries. Olenos is located in a high ground, nearby Ano Alissos, northern of Kamenitsa, by the archaeologists.

The Dymaia country was big enough and was included among the rivers: Piros from the east, Larissos from the west and Pinios from the South. In this very fertile country two remarkable cities have been established by the Iones in about 2000 B.C.: Olenos and Dymi. All ancient writers include these two cities in the list of the 12 Ionian cities, which were later renamed Achaia cities (from 1089 B.C.)

According to the Ancient Greek Mythology the "Olenian Goat" offered her milk to Zeus. Pelopas probably after he had settled in Olenos of Alissos, he became the king of Ilida. This is what professor Michael Sakellarios reports.

Hercules was offered hospitality by the king of Olenos, Dexamenos. Then, he killed the Centaur Evritionas, who had kidnapped Dexameno's daughter.

In about 1250 B.C. the Ilian people began invasions against the Iones of Olenos and Dymi. The second ones asked for help from Hercules. They built together "the wall of Dymi" which is saved totally in a very good situation at the village of Araxos, near the Strofilia forest. It's one of the most ancient fortresses of Greece.

In 1400 B.C. the inhabitants of Olenos and of the area sent settlers to Lesvos, Samos, Rhodes and Chios. Their leader was Makareas. In about 1150 B.C. the hero of the Troan war, Kifeus from Olenos and Dymi established colonies in Cyprus.

The old archaeologist Alexander Ragavis reports in his "Greek" that: in 757 B.C. the "settlement" of Dymi was created by the union of the towns around. Like Festos, Thelpousa e.t.c. In the next years this settlement subordinated Olenos too and embodied the country Olenia.

In 281 B.C. Dymi played a leading part to the formation of the 2nd Confederation of Achaia and became its capital until 255 B.C. Afterwards, Egio became the capital from 227 to 222 B.C. Dymi played the leading part in the war of Achaia against Sparti. The king of Sparti, Kleomenis, campaigned against Dymi with 20.000 soldiers.

In 226 B.C. the people of Achaia confronted the Spartians in the battle of Ekatomvaiou, nearby Dymi. (But many archaeologists support that the area of Ekatomvaiou is near the village Kagadi). Their general was Aratos but finally they were defeated.

From 220 to 217 B.C. the focal point of the Allied War was between the Achaia and Etolian Confederation. From 200 to 140 B.C. the people from Dymi collided many times with the Romans and supported the independence of Greece by helping the Macedonians. That's why the Romans disliked Dymi. They robbed it many times and finally they destroyed it.

In 145 B.C. the democratics from Dymi rebelled against the Romans and the aristocratic that betrayed them. Their leader was "Sosos Tavromeneos". Dymi also appointed great Olympic winners: Ivotas and Patraikos in the 6th century B.C. Julius Ceasar created a colony in 47 B.C., the "Colonia Iulia Augusta Dymaerorum". This colony was the origin of the Christian - Byzantine city Achaia. In nowadays Kato Achaia.

The town of Achaia was probably established after the destruction and the devastation of Dymi (27 BC.) The first cell of the new town seemed to be the Roman colony. The city of Achaia was developed in the 4th century A.C. In 344 A.C. it was probably the anus of the Bishop who was called Ploutarchos.

During the Byzantine season it was a small town. In 1147 A.C. the Norman invaders after they had destroyed Patras and the whole West Achaia, took 15.000 captives and carried them at Sicily and Italy. They needed them to teach the silk growing and the process of silk. At that time Achaia was called Moreas.

On the 1st of May 1205 the Frank conqueror knights landed in Achaia in the bay of the salt-pan (Aliki). Their leader was Godefridos Bileaqduinos. They stayed for a few days in Achaia and built a fortress with bricks from the ancient and Roman ruins. After that they crimped the citizens and fought against Andravida and later against Patras and Korinthos.

The emperor of Instanbul John the 8th (1417-1418) and Konstantinos IΑ' had their base of operations the town of Kato Achaia and the suburbs Riolos, Arla, Fostaina. The second one stayed overnight in Kato Achaia on 3rd of January 1429. His headquarters was the village of Santameri where his wife Theodora died by difficult delivery.

In 1447 the Turkish possessed Achaia and destroyed it. In 1458 for the 2nd time the Turkish came with Mohammed himself as a leader. In March 1460 Thomas Palaiologos harassed the Turkish in Achaia and bombed its fortress. At the same year Mohammed destroyed Achaia again.

The Venetians had Achaia as an administrative and commercial center (1687-1715). In 1770 the Turkish - Albanians destroyed Achaia. The citizens left towards the mountains and later built the Ano Achaia. But perhaps, this town had been built in the Byzantine season over the ruins of Tithea.

On the 4th of June 1807 Theodoros Kolokotronis with 80 marines invaded in Kato Achaia, with the warship "Saint George". He burnt the storehouses and the fortress of the Turkish. The Aga Said's mills as well.

During the years of Revolution in 1821 Kato Achaia met a lot of adventures and was the apple of discord between the Greeks and the Turkish.

The names "Pelopponese" and "Moreas" came from Kato Achaia and have a close relationship with its history.

In 1822 the Turkish landed in the mouths of Piros and were defeated by the Greeks and their leader Nilos Boukouras.

During all the years of Revolution, K.Achaia was a bulwark of Greeks. Greeks had there a powerful fortress. In 1822 the Greek army was called up with Kolokotronis as a Commander-in-Chief.

From 1824 two war ships from Spetses stayed at the saltpan of K.Achaia and controlled the navigation of the Patras Gulf. The foods and guns from the Ionian Islands reached there with animals from Halandritsa.

In 1829 Theodoros Kolokotronis came again with a detachment squad to chase the robbers. He stayed for three days at the house of Hoidas.

In 1832 K.Achaia became the capital of Dymi. The seal of Dymi had as an emblem an athlete who throws with a sling. It was established as the official emblem of the municipality of K.Achaia from 1991.

In nowadays, the city of K.Achaia is the capital of the new municipality of Dymi, which was formed from 1998. Today this municipality includes 7 municipal departments (ex-communities). The old Municipality of Dymi, which was operated from 1832 but was formed officially from 1835, included 40 villages and covered the whole ancient country of Dymi.