The Catacombs of San Gennaro are located on two non-overlapping levels, both characterized by extremely large spaces (6,000 square meters in all), unlike the most famous Roman catacombs. This is thanks to the workability and strength of the Neapolitan yellow turf.
The artistic heritage preserved in the catacombs spans from pagan elements of the 2nd century AD to Byzantine paintings of the 4th and 5th centuries AD. The original nucleus of the Catacombs of San Gennaro dates back to the 2nd century AD. It probably refers to the tomb of a noble family who then donated the space to the Christian community.
The expansion began in the 4th century AD, following the deposition of the remains of St. Agrippinus, first patron saint of Naples, in the underground basilica dedicated to him. Wide spaces and regular shapes silently greet the visitor in a timeless place. The imposing lower vestibule, with ceilings up to 6 meters high, houses a large baptismal font commissioned by Bishop Paul II, who in the eighth century took refuge in the Catacombs of San Gennaro during the iconoclastic crisis. One of the most impressive areas is the vestibule of the upper catacomb; it was decorated at the beginning of the third century in the so-called Pompeian style and holds the first Christian paintings of southern Italy.
Perhaps the most valuable area is the Crypt of the Bishops, which houses precious mosaics of the fifth century, including one representing San Quodvultdeus, Bishop of Carthage.