The following is a list of usurpers in the Roman Empire. For an overview of the problem and consequences of usurpation, see Roman usurpers. In the Eastern Roman Empire (395–1453), rebellion and usurpation were so notoriously frequent (in the vision of the medieval West, where usurpation was rare) that the modern term "byzantine" became a byword for political intrigue and conspiracy. For usurpation in the Eastern Roman Empire, see List of Byzantine usurpers.
The following individuals began as usurpers, but became the legitimate emperor either by establishing uncontested control of the empire or by confirmation of their position by the Roman Senate or by the legitimate emperor.
Most Western emperors were accepted by the Roman Senate (possibly except for Constans II) but almost never recognized as colleagues by the Eastern Emperors.[1] Three of them, (Constantine III, Priscus Attalus, and Constans II), reigned alongside the legitimate Emperor of the West Honorius, who accepted Constantine III as his co-emperor in 409. Upon his recognition, Constantine III appointed his son Constans II co-emperor.
The following individuals proclaimed themselves emperor (or were proclaimed or appointed as emperor), but are not considered as legitimate emperors because they did not oust the ruling emperor, or did not establish control of the whole empire, or were not accepted by the senate or other imperial colleagues.
They are listed here under the emperor whose rule they attempted to usurp. The noted date is the attempted year of usurpation.
Avidius Cassius (175), in Egypt and Syria, governor of Syria, declared himself emperor upon the rumor that Marcus Aurelius had died, continued his revolt even upon learning Marcus Aurelius was alive.
Censorinus (269–kS.270), almost certainly non-existent: "attested" only by the Augustan History (Trig. Tyr. 33) with no literary, epigraphical, numismatic support of any kind.
Sponsianus in Dacia, contested numismatic evidence only
Domitianus (270–271) most probably in Southern Gaul. He was probably encouraged by Aurelian's difficulties in dealing with an Alamannic incursion into Italy that occurred early in his reign. His bid for power could have been suppressed by Aurelian's Praetorian Prefect, Placidianus who was in the Rhone valley at the time or by Tetricus, the Gallic Emperor.
Felicissimus (k.271) in Rome, a civil servant involved in corruption