Centuries of calcium deposits were removed with lasers to reveal the earliest known images of the apostles Andrew and John, in work being carried out in the St Tecla catacomb in Rome. All previous known images of Andrew and John are from the mid 5th century.

The project leader Barbara Mazzei commented that the late 4th century image “….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”.

The work, in the tomb of a Roman noblewoman, is being carried out under the supervision of the Vatican's pontifical commission for sacred archaeology. Andrew and John are not alone. Images of the apostles Peter and Paul, as well as Jesus scenes from the bible have also been exposed by the removal of the calcium. Mazzei explained, "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." Many of the images are set against rich ochre, red and black backgrounds.

The St Tecla catacomb, which has not yet been seen by the public, was discovered in the 1950s. It is close to the basilica of St Paul's Outside the Walls and is currently accessed through the basement of an office building.

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