he Catacombs of Domitilla extend along the ancient Via Ardeatina on the site of the properties of the noblewoman Flavia Domitilla, the niece of Flavio Clemente, a consul from 95 A.D., who married a niece of Emperor Domitian (81-96) who was also called Flavia Domitilla. This part of the gens Flavia apparently had Christian sympathies because we know from the historians of the time that Domitian had Flavio Clemente condemned to death for religious reasons, and that his wife and niece were exiled to the Pontine Islands. Before their exile, the consul’s niece put her possessions on the Ardeatina at the disposal of the Christian community where the largest Christian underground cemetery of Rome would later originate.

The most important martyrs of the cemetery are Nereus and Achilleus, two soldiers who were probably victims of Diocletian’s persecution (304 A.D.). They were buried in the basilica, a majestic apsed hall from the time of Pope Siricius (385-399), which is preceded by a narthex and subdivided into three naves by columns with reutilized capitals. Another very ancient nucleus is the hypogeum of the Flavi. This originated at the end of the second century A.D. as a private, pagan hypogeum which later, during the third century, housed Christian tombs decorated with scenes from Sacred Scripture. The visit is complete with the cubiculum of Veneranda, the arcosolium of the Little Apostles, and the cubiculum of the grave-digger, Diogenes.

Source: Holy See - Catacombs of Rome

he Catacomb of Domitilla, located along the Via delle Sette Chiese just west of Via Ardeatina, is named after the owner of the land in which the catacomb was dug. Domitilla was a member of the Roman imperial family and was not a Christian; nor does the catacomb date from her lifetime. In the 2nd century, her descendents built a series of pagan catacombs on the land inherited from her, and in the 4th century they were reused by Christians. Linked with an existing Christian catacomb, the whole complex become known as the Catacomb of Domitilla.

In the early 4th century, the martyrs Nereus and Archilleus were buried in a cubiculum on the third level of the catacomb. Their tombs attracted many pilgrims, and Pope Damasus (366-84) enlarged the cubiculum to make room for them. After the early 5th century pilgrims also venerated the tomb of St. Petronilla, who was believed to be St. Peter's daughter.

Beginning in about 600 AD, a major construction project created an underground basilica by hallowing out the area around the tombs of Nereus and Archilleus. The Catacomb of Domitilla remained in use until the early 9th century, after which the saints' relics were transferred to the Church of Sant'Adriano in the Forum. The catacomb was then abandoned until its rediscovery in 1873.

A cubiculum in the Catacomb of Domitilla contains a fresco that is the earliest known depiction of Christ as the Good Shepherd. Other notable artworks include a late 4th-century relief of the martyrdom of St. Achilleus and a 4th-century fresco of a deceased woman named Veneranda being led into Paradise by St. Petronilla.

There is also an important 4th-century mosaic of the Raising of Lazarus, the Three Hebrews in the Furnace, and Christ Enthroned between Sts. Peter and Paul. Mosaics are very rarely found in the catacombs, and this one is important not only for its images but for the inscription accompanying the portrait of Christ: "You who are called the Son are found to be also the Father." This may reflect the sect (later declared a heresy) called Modalism, which explains that God is one being who variously expresses himself as Father, Son and Spirit.

The Catacomb of Domitilla can be visited on guided tours, with reduced tours during the busy summer to preserve the site. Unfortunately the parts with the most frescoes can only be visited with special permission.

Source: Sacred Destinations - Early Christian Catacombs, Rome