The archaeologists were surveying an undated but ancient breakwater that had been 160m long and at least 40m wide, constructed from large granite blocks on a rubble base to protect the island’s central port from strong winds. Sea-level has risen 2m since ancient times, leaving the structure under water.

Remains of walls, a colonnade, and three shipwrecks from around 100 BC, one carrying amphoras of oil and wine, were found off the southern tip of the island and at Rineia in Fylladi Bay. During the period, Delos - located in the Cyclades archipelago -  was at the height of its prosperity but declined after being sacked.

The styles of amphora discovered suggested that Delos had links with traders from as far afield as Italy, Spain and North Africa, and some dated back as far as the 5th century BC.

“The finds confirm that Delos was an important trading base and an important maritime trade route through the ages, linking the east and west Mediterranean,” said the ministry.

The excavation was carried out by Greece's Ephorate of Underwater Antiquities in collaboration with the French Archaeological School, the head of the ongoing Delos excavations Dr Jean Charles Moretti, and Dr Mantha Zarmakoupi of the National Hellenic Research Foundation

The divers also took the opportunity to photograph and map two shipwrecks found on earlier missions, at Kato Kerenale and near Fournoi.

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