The Basilica of San Clemente in Rome offers an unusually vivid look at the city’s layers of history. A short walk from the Colosseum, the modest-looking medieval church stands above an earlier basilica and Roman-era buildings, including a sanctuary dedicated to Mithras. Descending through the site means travelling from the twelfth century back towards ancient Rome.
The upper church is worth time in its own right. Its golden apse mosaic, known as the Triumph of the Cross, is filled with curling vines, birds and small figures, while the Chapel of St Catherine contains Renaissance frescoes by Masolino. Dedicated to Pope Clement I, an early successor of St Peter, the basilica has long been cared for by the Irish Dominicans.
Below, faded frescoes survive in the fourth-century church, and narrow passages lead to the Mithraeum, where followers of the Roman cult of Mithras once gathered. On the lowest level, the sound of running water adds to the atmosphere. The contrast between the luminous medieval church and the cool, enclosed spaces beneath it makes San Clemente one of Rome’s most memorable archaeological visits.
Entry to the upper basilica is free, but the excavations require a ticket; check current opening hours before visiting, as they can change around services and holidays. Cover shoulders and knees in the church, and wear sturdy shoes for the stairs and uneven underground passages. Allow about an hour for the visit.