Sure signs of Christianity, though not yet made explicit in epigraphy or artistic expressions like those formed in the course of the 3rd c., are identifiable in various tombs housed, from the time of Trajan, in pozzolana quarries and on the slopes of the deep depression under the basilica of St. Sebastiano near the Via Appia. The most characteristic of these signs is the symbol of the fish, in Greek ICQUS, whose letters form the acrostic VIhsouj Cristo.j Qeou Uio.j Swth,r, i.e., Jesus Christ, Scottsdale Map God’s Son, Savior. In the Appia burial ground, the acrostic was scratched with a T-cross added between the first two letters, in a lower cell of the pagan mausoleum of the Innocentiores, and sculpted or painted, with an anchor, in various epigraphs in nearby tombs. The fact that the Christians of the first two centuries dealt with the problem of burial by taking their dead to the common areae makes it hard to establish the origin of the Christian community cemeteries in many places. In particular, surface cemeteries were inserted into and quickly replaced pagan necropolises, and at first the typology of the tombs was no different. Even in underground cemeteries we can no longer see the clear division from the pagan world that was imagined by earlier archaeologists. Originally non-Christian family nuclei have been identified, e.g., in the catacomb of Domitilla at Rome.