Beneath the waters of the Bay of Naples, archaeologists are uncovering the remains of what was once the Roman Empire’s most important commercial gateway, revealing an extraordinary submerged city that has lain hidden for centuries.
Just three to five metres below the surface near modern-day Pozzuoli, researchers are documenting warehouses, workshops, porticoes and harbour infrastructure that once formed the bustling port of ancient Puteoli. The site, preserved underwater after centuries of volcanic ground movement, is providing an unprecedented glimpse into the economic heart of Imperial Rome.
Ancient Rome Live (ARL) Director Darius Arya recently joined underwater archaeologist Dr Michele Stefanile for a series of dives lasting nearly an hour each, navigating through remarkably preserved Roman structures, including a marble-cutting workshop and walls that still contain original wooden elements after almost 2,000 years beneath the sea.
Rome’s Original Commercial Lifeline
Long before the construction of Portus and the expansion of Ostia, Puteoli served as Rome’s principal commercial port. Situated on the Bay of Naples, the thriving city connected the capital to trade routes across the Mediterranean.
But the coastline gradually subsided over the centuries due to bradyseism, a unique volcanic effect occurring in the Campi Flegrei region which causes the ground to rise and fall over long periods of time. As a result, nearly two kilometres of the ancient harbour district are underwater.
A large archaeological programme from 2021 to 2027, led by Dr Stefanile of the Istituto Italiano per l’Archeologia Marittima e delle Strutture Sommerse, is presently documenting the submerged landscape. Funded by Ancient Rome Live’s Expandere Conscientiae Lumen (ECL) Grant, the project combines remotely operated vehicles (ROVs), photogrammetry, 3D modelling and GIS mapping to reconstruct the ancient port.
Lost Temple Rediscovered
Among the expedition’s most significant achievements is the rediscovery of the submerged Temple of the Nabataeans, believed to be the only Nabataean temple ever identified outside the Nabataean Kingdom.
Although the temple was first located during the 1980s, a lack of funding prevented further investigation, leaving it effectively forgotten for decades. After nearly 20 years of searching, Stefanile’s team successfully relocated the structure during the project’s first survey campaign in 2021. Initial excavation revealed the temple to be exceptionally well preserved, protected beneath layers of Roman concrete laid during the 2nd century AD following Emperor Trajan’s annexation of the Nabataean Kingdom.
Unlocking the Secrets of Rome’s Grain Supply
Researchers believe the submerged granaries of the vicus Annianus could become one of the project’s most important discoveries.
These vast storage facilities once handled grain shipments arriving from Egypt before they entered Rome’s food distribution network. Archaeological evidence aligns closely with surviving literary sources and the famous wax tablets of the Sulpicii, a Puteolan banking family whose records document loans connected directly to grain storage at the site.
According to Dr Stefanile, the exceptional preservation of timber and internal fittings offers an unparalleled opportunity to study the organisation of a Roman granary.
“This may be the only site in the world where we can observe the internal organisation of a Roman granary in such detail,” he said.
Despite its historical significance, Puteoli has long remained overshadowed by more famous Roman sites.
Arya argues that the city’s importance has been underestimated.
“Puteoli deserves far more attention than it currently gets, because this was the port city of Rome and the empire—the great commercial hub before Portus was created at Ostia,” he said.
He noted that the city formed part of an extraordinary concentration of Roman power and wealth alongside Misenum, home to the imperial fleet, and Baiae, Rome’s celebrated luxury resort.
“Puteoli itself had a stadium, a massive basilica and an amphitheatre that predates the Colosseum,” Arya said. “This was one of the major cities of Imperial Rome, yet much of it has been lost beneath the sea.”
The research team ultimately hopes to transform the submerged archaeological landscape into an accessible heritage destination.
Sources : The American Institute for Roman Culture
