Three specific genres of evidence lend themselves to demographic analysis of Christian expansion: inscriptions, papyri and archaeological artefacts. Most pre-Constantinian funerary inscriptions have been discovered in Rome, in Phrygia in Asia Minor, in Roman Africa and possibly at Syracuse in Sicily. The archaeological evidence of pre-Constantinian Christianity is confined to a few localities. Rome dominates the overall picture. The earliest monuments consist of the catacombs that the bishops of Rome acquired from the early third century onwards. Pre-fourth-century papyri survive exclusively from Egypt. Like inscriptions, they are demotic documents. Except for a small number of second and early third-century fragments of the Septuagint and gospels, the papyri mostly belong to the late third century and were written for family or business purposes. The expansion of Christianity is hardest to trace in the smaller provincial towns of the African provinces. Christianity expanded more quickly in the eastern Mediterranean coastal cities, and soon penetrated the hinterlands of Asia Minor.