Basilica of San Clemente

San Clemente is the clearest cross-section of Rome available. At street level is a twelfth-century basilica with a gold apse mosaic of the Tree of Life, vines spreading from the cross across the whole vault. Beneath it lies a fourth-century church, buried and forgotten until an Irish Dominican prior began digging in 1857, with frescoes including a scene whose caption is among the earliest written Italian, and it is unprintable. Below that again is a first-century Roman house and a Mithraeum, a temple to Mithras with its altar showing the god killing a bull, and an underground stream still running audibly past it.

History

The building grew from a private house, a place of secret Christian worship in the 1st century, into a large public basilica by the 6th. Its lowest levels hold the foundations of a building of perhaps the republican era that may have burned in the Great Fire of 64, and an industrial building, probably the imperial mint of Rome (Wikipedia, San Clemente, Rome).

What to look for

• The Tree of Life mosaic - a twelfth-century gold apse in the upper church.
• The fourth-century frescoes - including an early line of written Italian.
• The Mithraeum - a temple to Mithras with the bull-slaying altar.
• The underground stream - water audible on the lowest level.

When to go

Year-round; the lower levels are cool in summer. It closes over lunch and on Sunday mornings. Photography is prohibited on the excavated levels.

Good to know

The lower levels are damp, and photography is banned there. Stairs are narrow and the descent is not accessible. Ticket queues form in season despite the small entrance.

Nearby

The Colosseum lies west; the Lateran is east.

Key facts