The Catacombs of Domitilla are placed in the ancient praedium Domitillae, according to various literary sources and epigraphic findings. The catacombs owe their name to one of the two Flavia Domitilla of the Flavi’s family, converted to Christianity and therefore victims of persecution. Archaeological excavations conducted in the 20th century, allowed researchers to discover burial grounds dated back to the end of the Republican period (1st century B.C.). The cemetery kept expanding until the end of the Roman Empire, because members of noble Christian families wished to be buried near martyrs' relics. The underground cemetery development dates back to the 2nd – 3rd century. It was originally composed of different burial chambers, later joined into a single catacomb.