The Catacombs of Alexandria

Catacombs, network of galleries used for burial purposes by peoples of the ancient Mediterranean world, especially the early Christians. The word catacomb is probably derived from the Latin ad catacumbas, meaning "at the hollows," a phrase that referred to the chambers at a hollow south of Rome. The Romans at first buried their dead in family catacombs, which were excavated outside the city walls and protected by law, but later Romans preferred cremation. The Christians continued the practice of interring the dead in catacombs, which they called koimeteria, or "sleeping places," to suggest that, for a Christian,  death was merely sleep before resurrection. In its simplest form, a catacomb consisted of several underground galleries and chambers in a rectangular or grid plan. Loculi (recesses) were cut in the walls, one above another, to receive the bodies of from one to four family members. Persons of distinction were buried in stone coffins or carved sarcophagi placed in arched niches. The tombs of martyrs, usually in separate chambers, served as altars. As Christianity gained converts and burials multiplied, the catacombs were expanded into honeycombs of galleries. When one level was no longer sufficient, staircases were dug and levels of galleries were excavated below. Many of the catacombs of prominent Christians were decorated with wall paintings depicting Christian symbols, such as the fish, lamb, and anchor, or with biblical scenes. Similar motifs were carved on tombs.

 During times of persecution, the catacombs became places of refuge because burial places were sacrosanct by law. When churches above ground were destroyed by imperial order, worshipers met in the catacomb chapels. In the middle of the 3rd century, as mobs and officials began to violate the catacombs, Christians destroyed the old entrances and made secret ones. The persecution of the Christians came to an end with the conversion of the Roman emperor Constantine the Great in the 4th century. Soon after, Pope Damasus I began a monumental restoration of the catacombs. By the 5th century, however, all burials were transferred to surface cemeteries connected with churches. The catacombs, especially the tombs of martyrs, became places of pilgrimage.

In the unsettled period when Rome suffered waves of barbarian invaders, the catacombs were filled   in to prevent desecration, their entrances sealed, and the remains of the martyrs transported to places of safety. From the 16th century, abandoned catacombs were gradually restored by the Roman Catholic church. There are three levels in these tombs, the lowest of which is constantly under water due to the ground water.