The ruins of ancient Kymi, the city connected with the Greek colonization of the West, founder of the homonymous Italian colony of the eight century BC, stand on the hill of Viglatouri Oxylithou, in the area of modern Kymi. The site's privileged location in the middle of a fertile plain by the river Manikia (ancient Acheloos), from where it afforded excellent views of the sea, attracted settlers from prehistory until the Roman period.

The earliest traces of habitation in the area consist of a few Late Neolithic pottery sherds, and the earliest confirmed habitation phase at Kymi dates back to the Middle Helladic period (1900-1650 BC). The finds, a series of industrial installations, do not allow for safe conclusions regarding the nature of the settlement. Life on the hill continued throughtout the Mycenaean period, as the few architectural remains and pottery sherds from this period indicate.

Kymi thrived during the Geometric period. The Geometric settlement lies directly below the hilltop, on the hill's more easily accessible northeast slope. Unconfirmed evidence suggests that the settlement was fortified. Built over earlier architectural remains, it comprised a temple, a temenos, houses, squares, and streets. Because of its location, Geometric Kymi was an important city with contacts throughout the ancient world, a passage for people and goods to and from all directions. The plethora and variety of finds from the settlement support this opinion.

Strabo (first century BC) refers to the city of Kymi as having founded together with Chalkis the homonymous colony in the gulf of Naples: «Κύμη Χαλκιδαίων και Κυμαίων παλαιότατον κτίσμα. Οι δε τον στόλον άγοντες Ιπποκλής ο Κυμαίος και Μεγασθένης ο Χαλκιδεύς διωμολογήσαντο προς σφας αυτούς, των μεν αποικίαν είναι, των δε την επωνυμίαν, όθεν μεν προσαγορεύεται Κύμη, κτίσαι δ' αυτήν Χαλκιδείς δοκούσι». The citizens of these two Euboean cities set off in the last quarter of the eight century BC to colonize the West, covering extremely long, for that time, distances by sea and facing the dangers of an unknown world. Greek scholars, however, doubted the existence of ancient Kymi for more than one hundred years. The erratic references in ancient texts, the opinion that the Italian colony was founded by Aeolians, and, above all, the lack of archaeological evidence dating from the colonization period led to debate and skepticism. Recent excavations at Viglatouri by archaeologist E. Sapouna-Sakelaraki provided the necessary archaeological evidence. They began in 1984, continued for a decade, and were followed by conservation of the buildings.