Science is the intrinsic approach of human being to knowledge. The science of history is selfdefined in the socio-human field through concepts, normativity and methodology. The concepts represent an essential chapter due to the fact that they operate the theory of the scientific field. Our study intends to analyze the operational concepts involved in history’s research methodology. These become materialized within the abandonment of the static character of the field of research, during the period of Greek classicism because at this stage, history becomes detached from the sphere of influence of the myth. It becomes susceptible to periodization. Periodization operates on the basis of subdivisions called centuries. The historical era indicates a fracture in the succession of time. The concepts of age and generation succeed those of saeculum and aevum. They appear under the auspices of the Trinitarian Christianity, in the medieval period and refer to time as a measure of spiritual life. The delimitation of historical eras begins in the 14th century. Humanists operate a dual distinction according to the following paradigm: old means dark or dark means medieval. The conclusions of the study are underlining the importance of methodological research based on epistemological criteria. Though the operational conceptual apparatus is built only in the context of the foundation of history as a stand-alone science - in the 18th century, the process is essential in order to determine the status of history at the level of a specific domain of knowledge.