Very few human remains were found

What they found was a full fleet of 12 cargo ships that used to ferry grain to Rome.

Over 1,600 years ago, the fleet was sunk in an act of war in what was then the Port of Olbia.

"The Vandals came here, attacked the city and destroyed the ships," said the director of excavations, Professor Rubens D'oriano.

On the other hand, he added, the Romans might have destroyed their own ships to prevent them from being captured by the Vandals.

Scarce human remains

Hardly any human remains have been found from what must have been a scene of panic and bloodshed as Rome itself was overwhelmed.

In another corner of the archaeological site, heavy cranes were needed to lift a huge oak mast from what was a Roman shipyard.

This is one of the most important finds of the century

Eduardo Riccardi, naval archaeologist

The mast is about 2,000 years old, dating back to Emperor Nero, who murdered his mother and then his wife.

Naval archaeologist Eduardo Riccardi said this was the first ancient mast found in the Mediterranean.

"This is one of the most important finds of the century," Mr Riccardi said. "The fall of Rome is demonstrated here with these boats," he added.

Preservation

The boats are being taken to pieces and preserved for the moment in water-filled tanks.

Eventually, some will be reconstructed and moved into Olbia's new museum, by chance adjacent to the excavation.

The cargo ships used to ferry grain to Rome

Among the rare objects already dug up is a glass beaker from a chariot contest. Only one other such beaker exists - in the British Museum.

At the outset, the operation was dogged by red tape, an unsympathetic bureaucracy and a shortage of money.

The problems have been largely overcome and within six months Olbia will be able to complete its modernisation.

The archaeologists are also hurrying to excavate five medieval wrecks from the same buried port.