The 12th-century basilica was constructed on the foundations of a 4th-century church that was once a titulus, or private home converted into a place of Christian worship.
The Mithraeum contains a well-preserved stone altar showing Mithras slaying a bull, a central icon of the mystery cult.
Excavations in the mid-19th century were led by the Irish Dominican Prior Joseph Mullooly, who discovered the lower levels by clearing away rubble from centuries of neglect.
The 4th-century basilica was largely destroyed during the Norman sack of Rome in 1084, leading to the construction of the current church on top of the ruins.
The site includes a Roman insula (apartment block) that dates back to the Great Fire of Rome in 64 AD.
The apse mosaic features an elaborate acanthus scroll pattern that is considered one of the finest examples of medieval Roman mosaic work.
St. Jerome is associated with the early church, as it is believed he lived here during his time in Rome.
The sound of running water heard in the lowest levels is part of an ancient drainage system that still functions today.
The Basilica of San Clemente is a multi-layered archaeological site consisting of three distinct levels representing different historical eras. The ground level features a 12th-century basilica built over an older 4th-century church. Beneath the 4th-century structure lies a 1st-century Roman house and a 2nd-century Mithraeum dedicated to the god Mithras. This site provides a vertical cross-section of Rome's evolution from the Imperial period through the Medieval era. Visitors descend through time, starting at the current church floor and moving down to the Roman street level. The lowest level remains partially flooded by an ancient subterranean stream. The 12th-century basilica is renowned for its 12th-century apse mosaic depicting the Tree of Life. The site is actively managed and maintained by the Irish Dominican Order.
The 12th-century apse mosaic in the upper basilica.
Bring a light jacket, as the temperature significantly drops when descending into the subterranean Roman levels.
Photography is strictly prohibited in the underground excavation area to protect the ancient frescoes and masonry.
Visit the upper basilica first to appreciate the contrast between the ornate medieval church and the rugged archaeological levels below.
Do not attempt to touch the ancient walls or frescoes, as oils from skin cause rapid degradation.
Shoulders and knees must be covered to enter the active basilica; silence is required in the church areas.
