|Emperor of the Gallic Empire|
Coin featuring Postumus.
|Full name||Marcus Cassianius Latinius Postumus (prior to accession);
Imperator Caesar Marcus Cassianus Latinius Postumus Pius Felix Augustus Germanicus Maximus (as emperor)
|Place of death||Mogontiacum|
|Predecessor||Gallienus (as ruler of the united Roman Empire)|
|Successor||Marcus Aurelius Marius|
Marcus Cassianius Latinius Postumus was a western Roman emperor of provincial origin. He usurped power from Gallienus around the year 260 and assumed the title and powers of emperor in the western provinces of Gaul, Germania, Britannia and Hispania, thereby founding what scholars have dubbed the Gallic Empire. He ruled for the better part of ten years before he was murdered by his own troops.
Rise to power 
Little is known about the early life of Postumus. He has been claimed as a Batavian; certainly his coinage honours deities—Hercules Magusanus and Hercules Deusoniensis—who would have been popular among the Batavians. Deusoniensis may refer to the town of Deuso, located in or near Batavian territory and likely to be identified with Diessen; Postumus himself has been hypothesized to have been born in Deuso. From these relatively obscure provincial origins, Postumus would have risen through the ranks of the army until he held command of the Roman forces "among the Celts". What his precise title was is not definitely known, though he may plausibly have been promoted by the emperor Valerian to the position of imperial legate of Lower Germany.
By 259, Valerian was campaigning in the east against the Persians, while his son and co-emperor Gallienus was preoccupied with the situation on the Danubian frontier. Consequently Gallienus left his son, Saloninus, and military commanders, including Postumus, to protect the Rhine. Amid the chaos of an invasion by the Alamanni and Franks, and spurred on by news of the defeat and capture of Valerian, the army in Gaul revolted and proclaimed Postumus emperor.
The trigger was their defeat in 260 of a Juthungi army which was returning from Italy laden with prisoners, even though they had been repulsed by Gallienus at Mediolanum. Under the command of Postumus and Marcus Simplicinius Genialis, the Roman army crushed the Juthungi, and Postumus proceeded to distribute the captured spoils to the legions he commanded. Saloninus, on the advice of his praetorian prefect Silvanus (who had coordinated Roman policy in Gaul alongside Postumus), demanded the transfer of the recovered booty to his residence at Colonia Claudia Ara Agrippinensium. Infuriated by this command, the troops proclaimed Postumus emperor and proceeded to besiege and attack Colonia Claudia Ara Agrippinensium, trapping Saloninus and Silvanus. After breaching the walls of the city, Postumus had Silvanus and Saloninus killed, although his supporters later claimed that it was the native Gauls who were responsible for the murders. Later he erected a triumphal arch to celebrate his victory.
Postumus was immediately recognized as emperor in Gaul (except for Narbonensis), the two Germanias, and Raetia. By 261, Britannia and Hispania had also acknowledged him as emperor. He established his capital at Colonia Claudia Ara Agrippinensium and then proceeded to set up many of the traditional Roman legislative and executive structures. Apart from the position of emperor, he immediately assumed the office of consul alongside a colleague, Honoratianus. Like his imperial predecessors, he became the pontifex maximus of the state and assumed tribunician power each year. He established a senate and a praetorian guard. Reflecting his power base, the chief members of Postumus’ administration appeared to have been of northern Gallic origin, and indeed, the entire administration soon became rapidly Gallicized. Both Victorinus and Tetricus, important members of the government, hailed from this region.
Postumus represented himself as the restorer of Gaul (Restitutor Galliarum) and the bringer of security to the provinces (Salus Provinciarum) on some of his coins; prior to 10 December 261, he also took the title of Germanicus maximus, a title he earned after successfully defending Gaul against the Germans. His principal objective in assuming the purple appeared to be the restoration and defence of the Rhine frontier and the surrounding area, a task that he approached with vigour, earning the admiration of the ancient authors, who declared that he restored the security that the provinces had enjoyed in the past. So successful was he in the task of restoring peace and security to the provinces under his direct control that the coins issued by Postumus were of better workmanship and higher precious metal content than coins issued by Gallienus. After having spent four years pushing the Franks out of Gaul, Postumus then recruited Frankish troops to fight against other Franks, probably dispersed within existing Roman army units.
There is still considerable debate as to what Postumus’ ultimate aims were, whether he ever intended to usurp Gallienus or whether he was content to rule the western provinces. From the beginning of his usurpation, Postumus had made it clear that he had no intentions to make a bid for Rome, that his priority was for Gaul. Postumus' powerbase was Gaul and his main responsibility was the defense of the Rhine provinces. If he marched against Gallienus, then he would be exposing his heartland not only to the Germanic tribes but also potentially to any number of usurpers. Perhaps he hoped to achieve some official recognition from Gallienus; what is clear however, is that Postumus had no intention of creating a separate “Galliarum imperium”.
For four years Gallienus had been too distracted by Germanic invasions and other usurpers in the east to turn his attention to the situation to his north and west. This changed in 265 when Gallienus launched a campaign to defeat Postumus. After some initial success against Postumus, his first attempt failed when Postumus managed to escape from a precarious situation due to the carelessness of Gallienus' cavalry commander Aureolus, leading to Aureolus’ demotion and eventual abandonment of Gallienus in 267. A second campaign, led by Gallienus himself, also seemed to have the advantage over Postumus, but while Gallienus was besieging a city in Gaul (probably Augusta Treverorum), he was wounded and forced to withdraw. After his failed attempt at defeating Postumus, Gallienus was occupied with crises in the rest of his empire and did not have any further opportunities to challenge Postumus again. Gallienus nevertheless did manage to wrest control of Raetia from Postumus during these years.
By the end of 265, Postumus' coins were proudly announcing his victory over Gallienus, and the festivities celebrating his quinquennalia continued into the following year. Very little troubled the reign of Postumus throughout 267, but a sudden deterioration in the coinage in 268 shows that Postumus was facing increasing difficulties, resulting in the need to buy off an increasingly discontented army.
Nevertheless, Postumus was given a golden opportunity in 268 to move against Gallienus when Aureolus, Gallienus’ general who was in command of Mediolanum, openly changed sides and declared for Postumus. The city of Mediolanum would have been critical to Postumus if he planned to march on Rome. For whatever reason, Postumus failed to support Aureolus, who was besieged by Gallienus. Before the end of the northern summer in 268, the events at Mediolanum were to see the assassination of Gallienus, the defeat of Aureolus, and the accession of Claudius II. It also triggered a sequence of events that would see the end of Postumus’ rule in Gaul.
Postumus began his fifth consulship on 1 January, 269, but the army, unhappy with Postumus’ decision not to march on Rome in support of Aureolus, raised a usurper in early 269. Laelianus, one of Postumus' top military leaders and the governor of Germania Superior, was declared emperor in Mogontiacum by the local garrison and surrounding troops (Legio XXII Primigenia). Although Postumus was able to quickly capture Mogontiacum and kill Laelianus, he was unable to control his own troops and they turned on him and killed him, since they were dissatisfied with him for not allowing them to sack the city of Mogontiacum.
Postumus is listed among the Thirty Tyrants in the Historia Augusta. Traditionally, it had been held that his reign began in 259; however, modern scholarship tends to support the belief that the summer or fall of 260 is the more likely date that he was hailed emperor.
Primary Sources 
- Aurelius Victor, Epitome de Caesaribus
- Aurelius Victor, Liber de Caesaribus
- Eutropius, Brevarium, Book 9
- Historia Augusta, Tyranni_XXX*.html The Thirty Tyrants
- Joannes Zonaras, Compendium of History extract: Zonaras: Alexander Severus to Diocletian: 222–284
- Zosimus, Historia Nova
Secondary Sources 
- Canduci, Alexander (2010), Triumph & Tragedy: The Rise and Fall of Rome's Immortal Emperors, Pier 9, ISBN 978-1-74196-598-8
- Drinkwater, J. F. (1987), The Gallic Empire: Separatism and continuity in the north-western provinces of the Roman Empire, A.D. 260–274, Franz Steiner Verlag Wiesbaden GMBH, Stuttgart, 1987, ISBN 3-515-04806-5
- Jones, A.H.M., Martindale, J.R. (1971), The Prosopography of the Later Roman Empire, Vol. I: AD260-395, Cambridge University Press
- Polfer, Michel (2000), "Postumus (A.D. 260-269)", De Imperatoribus Romanis
- Potter, David Stone (2004), The Roman Empire at Bay, AD 180-395, Routledge
- Southern, Pat (2001), The Roman Empire from Severus to Constantine, Routledge
- Potter, p. 260
- Martindale, p. 720
- The year of Postumus' accession was either 259 or 260. Most scholars, according to J.F. Drinkwater (1987, p. 97), favour the latter date. The exact dating depends on several factors, including when the emperor Valerian was captured and disgraced. Other dates cited in this article must be pushed forward by one year for those who take 259 as the year of Postumus' accession. See Drinkwater 1987, pp. 95-106.
- Based on numismatic evidence, Postumus' rule extended over ten periods of tribunician power, each conventionally lasting for one year beginning on December 10. Regardless of which year Postumus assumed the purple (259 or 260), his rule must have stretched across ten such years. See Drinkwater 1987, pp. 93, 95.
- State, Paul F., A Brief History of the Netherlands, Infobase Publishing, 2008, p. 8
- Drinkwater 1987, pp. 162-3.
- "Regionaal Archief Tilburg - II. Romeinen in Deusone" (in Dutch). Retrieved 30 March 2013.
- The phrase is Zosimus', quoted in Drinkwater 1987, p. 59.
- Drinkwater 1987, p. 25.
- Potter, p. 257
- Southern, p. 79
- Polfer, Postumus
- Potter, p. 256; Canduci, p. 88
- Potter, p. 256
- Southern, p. 98
- Southern, p. 97
- Polfer, Postumus; Canduci, p. 88
- Potter, p. 261.
- Southern, p. 118
- Southern, p. 217
- Potter, p. 263
- Southern, p. 100
- Southern, p. 100; Canduci, p. 89
- Southern, p. 106; Canduci, p. 89
- Potter, p. 264
- Polfer, Postumus; Potter, p. 265
- Polfer, Postumus; Canduci, p. 89; Aurelius Victor 33.8; Eutropius 9.9.1
- Potter, p. 266
|Wikimedia Commons has media related to: Postumus|
- Partial coinage of Postumus
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