St Clement’s Basilica – Apostolic Rome Underground Tour

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St Clement’s Basilica Underground Tour: Apostolic Rome

The St Clement’s Basilica Underground Tour takes you beneath the streets of Rome through nearly 2,000 years of Christian history. With an expert Catholic guide, explore a first-century house associated with Christians of the Apostolic Age, an ancient pagan temple, a fourth-century underground basilica and the magnificent twelfth-century church visible today.

This approximately one-hour tour also reveals ancient frescoes, golden mosaics and the sacred relics of St Clement, St Ignatius of Antioch and St Cyril.

A Christian House from the Apostolic Age

Descend to the deepest archaeological level beneath St Clement’s Basilica, where first-century Roman buildings survive from the time of the Apostles and the earliest Church. Your guide explains their association with the first Christians of Rome and the tradition connecting this site with Pope St Clement, the third successor of St Peter.

Here the world of Apostolic Christianity comes into direct contact with imperial Rome, allowing visitors to understand the environment in which the early Church lived, worshipped and endured persecution.

An Ancient Pagan Temple

At the lowest level, discover an ancient Roman temple dedicated to the pagan god Mithras. Your guide explains the temple, its altar and the pagan culture within which Christianity first spread.

The surviving Roman buildings and ancient alleyway reveal the physical world of the first and second centuries beneath the later Christian basilicas.

The Underground Fourth-Century Basilica

Climb into the remains of the fourth-century Basilica of St Clement, created after Christianity emerged from persecution and could worship publicly. This buried church preserves remarkable medieval frescoes illustrating the saints, martyrs and developing life of the Catholic Church.

The excavations began in 1857 under the Irish Dominican Fr Joseph Mullooly, revealing the forgotten basilica and the still earlier Roman level beneath it.

The Twelfth-Century Basilica and Mosaics

Return to the present twelfth-century Basilica of St Clement. Its apse mosaic presents the Cross as the source of life, surrounded by imagery rich in scriptural and theological meaning. Your Catholic guide helps you read this sacred art and understand how it connects Christ’s Passion with the life of the Church.

The basilica’s ancient marble choir enclosure, Cosmatesque floor and layers of reused architecture complete a journey through the continuity of Catholic worship in Rome.

Relics of St Clement, St Ignatius and St Cyril

Venerate the relics of Pope St Clement and St Ignatius of Antioch, two great martyrs of the early Church. You will also visit the tomb and relics of St Cyril, Apostle to the Slavs.

St Cyril and his brother St Methodius brought the relics of St Clement from Crimea to Rome. St Cyril later died in Rome and was buried at this basilica, where his tomb and surviving relics are venerated.

Continue Your Journey through Early Christianity

For a longer pilgrimage, our Early Christianity Tour continues from St Clement to the Holy Stairs, St John Lateran—the Cathedral of Rome—and some relics of Christ’s Passion at Santa Croce. To explore further individual experiences, browse our Catholic Tours in Rome.

St Clement’s Basilica Underground Tour: further reading

Before your St Clement’s Basilica Underground Tour, read why San Clemente matters to Catholic history and discover how its successive levels reveal the continuity of Catholic Rome.

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