Roman imperial period (chronology)

The Roman imperial period is the expansion of political and cultural influence of the Roman Empire. The period begins with the Augustan reform, and it is taken to end variously between the late 3rd and the late 4th century. Technically, Late Antiquity would also count as "late Roman imperial period", up to the fall of the Western Roman Empire in AD 476, but the 5th century is mostly counted as part of the Migration Period, as the influence of Rome had become too weak to act as a dominant cultural force.

Thus, the term "Roman imperial period" has increasingly been used as opposed to "Late Antiquity", i.e. implying the "early" and "middle" imperial period of the late 1st century BC to the 3rd century AD. The "Roman imperial period" in this sense would end with the reforms under Diocletian (r. 284–305) and the beginning of the Christianization of the Roman Empire.

In historiography, the "imperial period" is by convention taken to last from 27 BC to AD 284. In archaeology, on the other hand, the term is usually taken to cover the period of c. AD 1 to 375 (the latter being a conventional date for the onset of the Migration period). This follows Eggers (1955), who used a periodization of "early imperial period" (in German, frühkaiserzeitlich) B1 to B2 and "late imperial period" (spätkaiserzeitlich) C1 to C3, reflecting the history of Roman pottery imports to Germania magna and other parts of Barbaricum (Eggers A corresponds to La Tène D). In the chronology of Eggers (1955):