he west harbour of Corinth lies 12 stades (approx. 2 km.) north of the city, on the coast of the Corinthian gulf. Originally this was a marsh, which was appropriately arranged in Archaic times (7th-6th century BC), by extensive digging and dredging works to deepen the area, as well as by strengthening the strip of land on the side of the open sea, which functioned as a breakwater. Lechaion became Corinthís main channel of communication with the western Mediterranean, as it was the port of departure of Corinthian ships intent on its commercial conquest and colonization. On account of its importance for the safety and viability of the city in times of peace, but also of war, the Long Walls were constructed, connecting the harbour to Corinth. Lechaionís importance is confirmed by Plutarchís testimony that the symposium for the Seven Sages, hosted by the tyrant Periander, was organized there, while Xenophon refers to its capture by the Spartan Agesilaos in the fourth century BC, in order to prevent the victualling of Corinth. Strabo mentions that in the first century BC Lechaion had few inhabitants and remained walled.
The founding of the Colonia Laus Iulia Corinthiensis, into the reign of Emperor Claudius (AD 41-54), prompted the upgrading of the harbour installations and the construction of moles, which are still visible today below sea level. One century later, Pausanias saw in Lechaion a sanctuary of Poseidon and the bronze statue of the god. The Roman harbour is represented on Corinthian coinage of the third century AD, while from the fourth century AD there is epigraphic testimony of works to improve the harbour facilities, carried out on the initiative of the vice-consul of the Province of Achaea, Flavius Hermogenes, whom the citizens honoured by erecting his portrait statue in the harbour area.
In the second half of the 5th century AD / early 6th century AD, a five-aisled Christian basilica of a total length of 180 m., was erected in the area, dedicated to the martyr Leonides.