The Gallic Empire or the Gallic Roman Empire are names used in modern historiography for a breakaway part of the Roman Empire that functioned de facto as a separate state from 260 to 274. It originated during the Crisis of the Third Century, when a series of Roman military leaders and aristocrats declared themselves emperors and took control of Gaul and adjacent provinces without attempting to conquer Italy or otherwise seize the central Roman administrative apparatus.
Coin of Tetricus, last emperor (271–274) of the Gallic Empire
The Roman Empire was the post-Republican state of ancient Rome. It is generally understood to mean the period and territory ruled by the Romans following Octavian's assumption of sole rule under the Principate in 27 BC. It included territories in Europe, North Africa, and Western Asia and was ruled by emperors. The fall of the Western Roman Empire in 476 AD conventionally marks the end of classical antiquity and the beginning of the Middle Ages.
Augustus of Prima Porta
Nerva (r. 96–98)
Trajan (r. 98–117)
Hadrian (r. 117–138)