The history of the Roman Empire is the history of a complex process of integration, often labeled “Romanization”. The receptiveness of Rome towards the Greeks and the incorporation of Greek culture into a Roman context are well-known themes in classical studies and archaeology. With the concept of “’the other’ in action“ we argue that this receptiveness of Roman culture is the basis of and thus the key concept for the understanding of the empire and the provincial system. It is about Rome’s unique capability to creatively adapt elements of foreign cultures, of “the other”, within the framework of Roman rule and to make them part of an integration process, involving culture and especially religion. Such a theoretical approach will investigate “’the other in action’” in a multi-disciplinary way, from multiple angles, including collaborators from Romania and from across Europe and centred on the fields of ancient history, archaeology and linguistics, thus covering Roman Italy, Germany, Dacia and Greece in a comparative perspective, and dealing with issues like military organization, linguistics, numismatics, religion. The main question underlying this approach is not how the process of “becoming Roman” took place, but why it was possible to “become Roman” while still being/staying Greek, Aleman, Goth or Dacian. “the ‘other’ in action” could be the first Romanian contribution to this crucial, ongoing debate, and a much-needed reappraisal of the concept of Romanization.