The Archbasilica of St John Lateran is the cathedral church in the city of Rome, Italy. It is the oldest and highest ranking of the four papal major basilicas, giving it the unique title of ‘Archbasilica.’ The church was originally built in the 4th century CE by Constantine the Great, a Roman Emperor who ruled between 306 and 337 CE and made Christianity the official religion of the Empire. Positioned on the Caelian Hill, the Archbasilica of St John Lateran would have dominated the Roman skyline at the time. As new research from the Lateran Project reveals, however, the site had already been in use for centuries.
To build the Archbasilica of St John Lateran, Constantine had swept away the Castra Nova (New Fort), the lavish headquarters of the imperial horseguard constructed over a century before by the Emperor Septimius Severus.
In much the same way, Severus had previously destroyed the palatial houses of some of Rome’s most powerful residents to make way for the horseguards’ impressive new home.
This ongoing process of construction on the site meant that over hundreds of years layers of Roman history were laid down, much of it reflecting the changing fortunes and priorities of the Empire.
Working far beneath the modern streets of Rome, archaeologists on the Lateran Project have brought to life the first ever holistic picture of hundreds of years of Roman history by using digital mapping, ground penetrating radar and 3D visualization techniques.
Working with some of the world’s leading visualization specialists, they have reconstructed the splendor of the buildings.
The work has also permitted study of how the different buildings that occupied the site evolved, how different elements relate to one another and has given a sense of the scale the four-hectare site covers.
“There is a large area of space underneath the Lateran that it is possible to walk or crawl through,” said Newcastle University’s Professor Ian Haynes, co-director of the Lateran Project.
“The archaeology is at varying levels below — at the deepest we were 8.5 m below modern ground surface.”
“To access some of the spaces we worked with a group called Roma Sotteranea who specialize in working on buried sites and use exactly the same equipment and techniques as potholers. In some places, it was necessary to rotate the teams on a half hourly basis because otherwise it just becomes stifling.”
The construction of the Archbasilica of St John Lateran was a pivotal moment marking the start of the major Christian buildings that came to define Rome and is a potent symbol of the military making way for religion.
In 312 CE, Constantine’s army fought the Battle of Milvian Bridge, after which the old Horse Guards base and several nearby buildings were destroyed.
The land was given to the Church and provided the perfect spot for Constantine to set out his new vision for Rome.
“The land may have been given to the Church within weeks of the battle. A decision was certainly taken pretty soon afterwards and work on the Lateran started some years before it did on St Peter’s,” Professor Haynes said.
“The cathedral was rebuilt in the 1650s but there is still original Constantine fabric in the walls, while the original foundations are exposed beneath the church.”
“There have been various efforts to reconstruct it since then, so we wanted to pull together all of this information to create a digital cathedral that you can walk around.”