Though the first archaeological finds go back to at least the 3rd millennium BC, the earliest structures are the walls of some Bronze Age buildings (2nd millennium BC), upon which many tombs of a Geometric graveyard (8th, 7th century BC) were built.
The area changed function in the 4th century BC, becoming the principal square of the city (agora) of 107 x 87 meters. A monumental entrance towards the residential quarters opened to the east. In the agora’s centre were numerous small sacred buildings and altars. Porticoes surrounding the square (stoa) date to the 2nd century AD. First construction was effectively never finished, as damage by earthquakes occurred. It was finished in the age of Justinian (6th century). In that period a Christian basilica was erected in the central-east zone of the agora. Around it was a vast necropolis, in use until the 15th century AD.
In Byzantine times inferior buildings rose among the collapsed colonnades, which often reemployed parts of columns and other ancient structures. Some industrial structures (furnaces for metal, glass and pottery) were set up along the east and south stoai in the 10th and 11th centuries. The remains of the agora became buries over time, its north-west corner was built upon by a medieval castrum near the isthmus, possible built in Byzantine times to defend against Arab and Persian threats in the 7th and 8th century.