For 2000 years the ancient and decomposing hulk lay buried in deep, muddy waters, off the Italian coast.
Everybody knew it was down there because for more than 80 years local fishermen had been collecting bits of Roman artefacts and pots in their nets.
Finds of this nature are not unusual in Italian waters, which are littered with treasures going back thousands of years.
But these artefacts told a different story, and it was good enough to attract the interest of the archaeological community and a police commander who heads an expert diving squad in the city of Genoa.
Lieutenant-Colonel Francesco Schilardi, the commanding officer of the police team that found the wreck, has been referred to as the ''Top Gun'' of the oceans because of the secrets he and his team unravel by locating and recovering wrecks and long-lost treasures.
This time the team, including state archaeologists and historians, were so sure that the ocean, close to the town of Varazze, Liguria, was hiding something special that they went to a little more expense to find out what was down there.
They used a submarine, a robot and sophisticated mapping and tracking equipment, along with the results of extensive historical studies of the area.