Ancient Roman Mosaic Floor Discovered in the Waters of Naples

The marble floor was once installed at the entrance to a Roman villa.

At one time, Baia was a closed seaside vacation spot for the Roman elite, and a very debauched one at that. It was the villa of Julius Caesar, as well as the emperors Augustus, Nero, and Caligula. The first-century BC poet Sextus Propertius called Bayi "a whirlpool of luxury" and "a haven of vice". It was not until the 1940s, however, that Rome's hedonist mecca was discovered underwater in the Gulf of Naples.

Since the late 1950s, marine archaeologists have been scouring the shoreline down the slopes of the Phlegrean Fields for treasures of a luxurious past. To date, divers have uncovered halls of marble statues, giant columns, ancient baths, fish ponds and ornate fountains, many of which have been moved to a museum adjacent to the Baia Underwater Archaeological Park.

Archaeologists have now uncovered the intricate marble floor of a Roman villa that adorned the entrance to a porch overlooking the sea. Unlike mosaic floors such as the one discovered in the spa last year, a team of divers from CSR Restauro Beni Culturali and Naumacos Underwater Archaeology and Technology have uncovered a rarer and more expensive flooring: opus sectile.

Whereas mosaic uses small stone squares called tesserae to create a pattern, opus sectile requires cutting stones into precise shapes and then forming complex patterns. The technique encouraged the use of expensive polychrome stones such as marble and became increasingly popular from the first century B.C. Famous examples include the Basilica of Junius Bassus in Rome and the floors of the Villa of Adrian.

As such, opus sectile were considerably more expensive than conventional mosaic floors - although at Bayeux, archaeologists noted that the owner used recycled materials.

One of the people excited about the discovery was the mayor of Bacoli. "Amazing. This is the magic of Baia underwater," Josi Gerardo Della Ragione wrote in a statement. "The largest underwater archaeological park in the world has found an opus sectile - a room for hosting receptions in a villa built at the end of the Roman Empire."

The site was rediscovered by Raimondo Baucher, an Italian Air Force pilot and pioneer diver who one day, flying low over the sea, noticed walls, columns and roads. Baucher's photographs aroused great interest, but it was not until 1959 and the development of diving equipment and marine archaeology that excavations could begin.

Bayi was lost to the sea between the third and fifth centuries when underground magma chambers caused the surrounding topography to fall, a process known as bradyseismic activity.