Archaeologists exploring a Christian catacomb under a residential Roman street have unearthed the earliest known images of the apostles Andrew and John.
Using a newly developed laser to burn away centuries of calcium deposits without damaging the paintings beneath, the team found the late 4th-century images in the richly decorated tomb of a Roman noblewoman.
"John's young face is familiar, but this is the most youthful portrayal of Andrew ever seen, very different from the old man with grey hair and wrinkles we know from medieval painting," said project leader Barbara Mazzei.
Discovered in the 1950s and as yet unseen by the public, the St Tecla catacomb is accessed through the unmarked basement door of a drab office building, beyond which dim corridors packed with burial spots wind off through damp tufa stone.
The catacomb is close to the basilica of St Paul's Outside the Walls, where bones discovered in a sarcophagus have been dated to the first or second century and attributed to St Paul.
Working under the supervision of the Vatican's pontifical commission for sacred archaeology, Mazzei first exposed images of fellow apostles Peter and Paul, as well as Jesus, and biblical scenes set against rich ochre, red and black backgrounds – colours commonly associated with imperial Roman art.
"The laser can be calibrated to remove certain colours, in this case the white of the calcium, which just fell away. We are used to finding faded colours, but here they are exceptional," she said.
As the calcium was burned off, John and Andrew appeared on the same ceiling panel as Peter and Paul.
"We already know earlier images of Peter and Paul from group paintings, but all previously known images of Andrew and John date to the mid 5th century," said Mazzei. "We assume it is them because they were the most important apostles after Peter and Paul and would have found space alongside them here."
Mazzei said the tomb was built by a noblewoman as Rome was switching from paganism to Christianity. "This catacomb was not a clandestine burial place, in fact they never were, that was an invention of Ben Hur," she said.