One of the criteria for identifying a portrait of a Roman emperor has been the existence of proven ancient replicas. This rule can no longer be maintained: ancient replicas can be established also in the case of portraits of non-imperial persons. This applies not only to the portraits of members of the upper class, but also to those of more ordinary citizens. The phenomenon may be found in all parts of the Roman Empire in which portraits were produced. The portraits that can be verifiably established at present have been brought together in this volume. Some cases have been known for a long time (Herodes Atticus, Athenais, Polydeukion), although no consequences have been drawn from this by researchers. Portrait replicas were not only set up in public places: above all, graves presented an opportunity to honor the deceased with multiple portraits. A corresponding context can be established in few cases, however, as portraits from this domain were generally separated as »doublets« by art dealers. Copies made of famous ancient portraits in modern times must be excluded from the group of ancient portrait replicas. In older research some of them were regarded as ancient copies and were mistakenly associated with Roman emperors and their family members on account of their supposed replica character. It is not always very easy, however, to prove production in the modern era. The most important specimens from this category are collected in Appendix B. Appendix A, meanwhile, brings together the multiple portraits of the same person at grave altars and sarcophagi, which may be seen as classic examples of private portraits with replicas.