The term Roman catacombs refers to an underground burial ground of several floors from the time of the first Christians. As Christians were initially heavily persecuted and the faith was not accepted by the public in the early days of Christianity, it was essential to create a burial place for believers and martyrs who died for the faith. The catacombs began to be built in the late 2nd century and were an ideal place to hold Christian ceremonies, visit the martyrs, and celebrate them with loved ones.
Until 313, the catacombs under Rome functioned as a kind of illegal Christian burial ground. This was changed by Emperor Constantine, who allowed religious freedom. The catacombs began to be further expanded and decorated. Another crucial period for the catacombs marks the decision of Pope Damasus. This pope had the tombs of early Christian martyrs repaired and wrote hymns celebrating their martyrdom.
The tombs of Christians in the catacombs are most often carved into the walls stacked upwards. The bodies were often strewn with natron and the grave was closed with an earthen terracotta slab.
In the time of Pope Damasus, some tombs of prominent martyrs were provided with slabs of marble with the name of the saint engraved in them. Inside the tombs were often clay or glass vessels filled with the supposed blood of the saint or oil lamps, which were originally used to illuminate the underground spaces of the catacombs. New archaeological analyses show that they were more likely to be fragrance oils and resins, rather than blood.
The greatest interest in the catacombs and the tombs of the saints occurred in 1578 when soil on one of the vineyards located on an ancient salt road of Via Salaria collapsed. This event led to the rediscovery of the catacombs and to an interest in exploring them. At the same time, the catacombs became a great source of relics of saints for the Church, and they were distributed to European catholic churches. Specialists, the so-called corpisantari, oversaw the removal of the relics.
The catacombs were considered a source of martyrs' bodies, but over time it was forgotten that the general Christian public was also buried there over the centuries. Thus, when the remains of the saints were removed in bulk, it was impossible to distinguish the original martyrs from the ordinary early Christians who lived in the vicinity of Rome and were buried there. All the remains from the catacombs were therefore venerated as saints.