Crisis of the 3rd Century&Growing Dangers of Trade

[Nathan Ross]

Did Postumus & his followers revolt because of Rome's inability to protect them during the barbarian invasions? Or was it out of greed and power? Or both?... With the growing dangers of trade between the provinces and Rome, did this danger help contribute to the extended economic deppresion of the crisis?... Why were their so many emperors?!

These are some big questions (and interconnected, of course), and they're difficult to answer as our sources for the period are fairly scrappy. Nevertheless, I'll try and put down a few thoughts that might lead to better answers or debate from others.

Postumus certainly seems to have promoted himself as a protector of the west - doing what the central government could not do - with his coin slogans of 'Restorer of Gaul' and 'Saviour of the Provinces'. It seems likely that he did (even if briefly) manage to contain the barbarian attacks on the Rhine frontier. But I suspect the reasons for his power bid, and its success, run more deeply.

By the later second century (or so) the process of Romanisation in the provinces of the empire had reached a sort of watershed. Infrastructure and urbanisation, trade networks, military deployment and economics were by that time fairly standard across the empire. There was little reason now for the provinces to defer to Rome, or look naturally to Italy for guidance in the maintenance of civilisation.

Coupled with this, imperial power itself had become decentralised. Since Hadrian, emperors had become peripatetic, travelling with their mobile courts around the provinces. There were exceptions (Antoninus Pius, for example), but the citizens of the empire were perhaps far less likely to equate the city of Rome with the centre of imperial power. The rise of the Severan dynasty - with its strong links with the African and Syrian aristocracies - had further widened the breach between imperial power and the urbs itself.

It's probably no coincidence that the reign of Valerian - another very mobile emperor! - also seems to have seen the first concerted efforts to shut the traditional senatorial elite out of military command. From Valerian onwards we see the rise of a new military cadre, based ultimately on the centurionate and loyal to the figure of the emperor himself rather than the traditional structures of senatorial power.

At the same time, the various barbarian peoples immediately outside the empire seem to have acquired a new cohesion and a sort of collective identity (at least in Rome eyes) - much larger groups like the Franks, Goths and Alamanni, capable of more concerted attacks deep inside the Roman frontiers. The massive defeats of mid century - Abrittus, and the capture of Valerian - further stretched the abilities of Roman central command to respond adequately to diverse barbarian attack and pressure from the resurgent Sassanid Persians.

Postumus was probably a Batavian, but his power base was in the western army and the Gallic aristocracy: his co-emperors and successors, Victorinus and Tetricus, were both Gallic landowners and senators. It's possible that the western senatorial aristocracy had been feeling marginalised since the Severans - many of their families may have backed Clodius Albinus back in AD195. This same sense of regional identification was at work in the east too, where many Roman officials seem to have initially supported Odenathus of Palmyra.

Quite what effect Postumus's usurption had on the economic prosperity of the west is probably impossible to judge. The Gallic provinces suffered greatly in the third century, if the amount of deserted agricultural land and abandoned villas by the end of the century is any evidence. How much of this was caused by Postumus and how much happened after him is hard to say.

However, the problem with a successful usurption is that it opens the door to further usurpers. Postumus seems to have been just as plagued by rivals as the central emperors, if not more so. Interestingly, two of these rivals - Laelianus and Marius - came specifically from the army. Marius was apparently a 'common soldier', whatever that might mean. Perhaps he was one of the able centurions that Valerian and Gallienus seemed keen to promote, and a precursor to the very effective 'barrack emperors' that followed.

Either way, with the emergence of Aurelian and the defeat of the Palmyrenes, it must have become clear to many in the west that their attempt at self-rule could not last, and would only further weaken their ability to defend themselves against the threat from across the Rhine. Tetricus, the last Gallic emperor, surrendered in a deal with Aurelian, leaving his army to die in his name...

(I should add that most of the above is drawing rather vaguely on the earlier chapters of David Potter's The Roman Empire at Bay, and the relevant bits of The Cambridge Ancient History, Volume 12: The Crisis of Empire, amongst other things... but I haven't looked back at them to check references...)

(p.p.s. I should mention that the above is probably quite a traditionalist view - there's a strand in recent scholarship that downplays the severity of the 'crisis', particularly in its effects on the prosperity of the provinces. I'm not sure about that - but that's for a wider discussion, maybe...)