The cathedral houses the Sarcophagus of the Labors of Hercules, one of the most significant pieces of Roman pagan sculpture repurposed for Christian use.
The site originally functioned as a temple to Mars before being converted into a place of Christian worship in the late Roman period.
The cathedral contains relics attributed to Saint Clemente I, which were allegedly brought to the city in the 9th century.
The Madonna delle Grazie icon is traditionally credited by locals with protecting the city from the plague during historical outbreaks.
It has historically served as a seat for the suburbicarian diocese, historically held by senior cardinals of the Roman Catholic Church.
Velletri Cathedral, formally the Basilica Cattedrale di San Clemente I, serves as the co-cathedral of the Diocese of Velletri-Segni. The current structure stands on the site of an ancient temple dedicated to Mars. Its Romanesque-style foundations date to the 4th century, though the building underwent significant Baroque reconstructions during the 17th century. The interior houses a notable collection of sacred art, including a 13th-century Byzantine-style icon of the Madonna delle Grazie. The crypt contains early Christian sarcophagi, most notably the Sarcophagus of the Labors of Hercules from the 2nd century AD. The bell tower, partially constructed with Roman brickwork, remains a distinct architectural feature of the Piazza S. Clemente skyline. It preserves the relics of San Clemente, the third successor of Saint Peter and patron saint of the city. The cathedral holds the title of minor basilica, granted to reflect its historical and ecclesiastical importance in the Castelli Romani region.
The view from the opposite side of Piazza S. Clemente offers the best perspective of the facade and the bell tower alignment.
Visit the Diocesan Museum located nearby to see religious artifacts and treasures not displayed inside the cathedral.
Look for the ancient Roman inscriptions and fragments of marble embedded in the exterior walls of the building.
Spend time walking the perimeter of the piazza to view the bell tower from multiple angles.
Do not attempt to enter during private religious ceremonies or weddings without prior permission.
May experience irregular closures during private liturgical celebrations; generally accessible outside of service times.
Shoulders and knees must be covered; maintain a quiet voice and avoid taking photos during active religious services.
