Case studies of Faustina the Younger's and Marcus Aurelius' portraits on coins and in sculpture demonstrate that a more flexible approach than currently allowed for is needed to describe ancient practices and processes behind the phenomenon of 'replicated' imperial portraits. Possible norms are investigated in this study, and an adjusted model of an imperial portrait 'system' in the second century A.D. is outlined. Key concepts of the prevailing model are the assumption of an official commissioning of all imperial portrait types, the view of a close correspondence between imperial coins and sculpture and the belief that types were created to commemorate specific historical events. All of this, however, is far from certain and a close examination of the preserved evidence makes it necessary to revise the model in certain ways.