The Mithraeum of Rome beneath the Basilica of St. Clement

Located in Rome, the Basilica of Saint Clement (Italian: Basilica di San Clemente al Laterano) is a Latin Catholic minor basilica dedicated to Pope Clement I. Beneath the present basilica, built just before the year 1100, lies a complex of older structures. The site includes the home of a Roman nobleman, which was built on the foundations of a republican era villa and warehouse destroyed in the Great Fire of AD 64. Shortly after an industrial building was constructed on the same site during the Flavian period, an insula, or apartment block, was also built, separated from the industrial building by a narrow alleyway.

In the 4th century, the lower level of the industrial building was filled in with dirt and rubble. Part of the domus was also filled in, including the courtyard of the insula where a mithraeum, a sanctuary of the cult of Mithras, was built around the year 200. The main cult room, or speleum, was discovered in 1867 but could not be investigated until 1914 due to a lack of drainage. The exedra, the shallow apse at the far end of the low vaulted space, was trimmed with pumice to render it more cave-like.

Central to the main room of the sanctuary was an altar in the shape of a sarcophagus, featuring a relief of the tauroctony, the image of Mithras slaying a bull. The torchbearers Cautes and Cautopates appear on the left and right faces of the same monument. A dedicatory inscription identifies the donor as one pater Cnaeus Arrius Claudianus. Other monuments found in the sanctuary include a bust of Sol kept in a niche near the entrance, a figure of Mithras petra generix, and fragments of statuary of the two torch bearers. All three are still on display in the mithraeum.

The present basilica features an atrium surrounded by arcades that now serves as a cloister. Fronting the atrium is the facade of Carlo Stefano Fontana, supported on antique columns. The church behind it has three naves divided by arcades on ancient marble or granite columns with Cosmatesque inlaid paving. In the presbytery is a ciborium raised on four gray-violet columns over the shrine of Clement in the crypt below, while the apse is covered with mosaics on the theme of the Triumph of the Cross.

Sources: Wikipedia, OpenStreetMap, Wikidata, Wikimedia Commons