The Gallic Empire (in Latin, imperium Galliarum) is the modern name for the independent realm that lived a brief existence during the Roman Empire's Crisis of the Third Century, from 259 to 274. The Gallic or Gallo-Roman Empire consisted of the break-away Roman provinces of Gaul, Britain, and Hispania, even peaceful Baetica in the south. The crisis was ignited when Emperor Valerian I was captured by the Sassanid Persians, leaving his son Gallienus in very shaky control. As governors in Pannonia staged unsuccessful revolts in Pannonia, this took the emperor to the Danube, leaving Postumus, who was governor of Upper and Lower Germany, in charge at the Rhine.
The imperial heir Saloninus and the praetorian prefect Silvanus remained at Colonia Agrippina (Cologne), to keep the young heir out of danger and perhaps also as a control on Postumus' ambitions. Before long, after some successful border skirmishes, Postumus took control of Colonia Agrippina, and put the young heir and his guardian to death.
Postumus set up the Empire's capital at Augusta Trevivorum Trier, in what is now the Rhineland-Palatinate of Germany, with its own senate, two annually elected consuls and its own praetorian guard. Postumus himself seems to have held the office of consul five times.
Beyond a mere symptom of chaos in the third century crisis, the Gallic Empire can be interpreted as a measure of provincial identification competing with the traditional sense of romanitas, of the cohesive loyalties of individual legions, and of the power accumulated by entrenched Romanized aristocratic kinship networks whose local power bases ranged from the Rhine to Baetica, although the extent of "Gaulish" self-identification that nationalist historians have inferred is probably inflated. Postumus declared his sole intention was to protect Gaul — this was his larger Imperial task — and in 261 he repelled mixed groups of Franks and Alamanni to hold the Rhine limes secure, though lands beyond the upper Rhine and Danube had to be abandoned to the barbarians within a couple of years.
The Empire also had its own series of consuls, but not all of the names of the consuls have survived.
Its emperors are known primarily from the coins they minted. The political and military history of the Gallic Empire can be sketched through their careers. Their names are as follows:
- Postumus 259 – 268
- (Laelianus 268, usurper)
- Marius 268
- Victorinus 268 – 270
- Tetricus I 270 – 273
- Tetricus II 270 – 273 (son of Tetricus; caesar)
|Roman Emperors by Epoch (see also: List – Concise List – Roman Empire)|
| -> (Italy:)|
-> (Much later in Western Europe:)
-> (Continuing in Eastern Europe:)