Roman Usurper - Instability

Instability

Commodus, the last emperor of the Antonine dynasty and remembered by contemporaneous chronicles as an unpopular ruler notorious for his extravagance and cruelty, was assassinated in 192. Without sons to be his heir, a struggle for power immediately broke out amongst the governors of the most important provinces. Pertinax was elevated to the purple and recognized by his peers, but following his murder by a restive Praetorian guard, Septimius Severus decided to make his bid for power and usurped the throne. Although initially a usurper, Severus managed to remain in power for the next 18 years and died a natural death while campaigning in northern Britain. His death in 211 triggered what historians call the crisis of the third century. In this period, from 211 to the accession of Diocletian and the establishment of the Tetrarchy in 286, Rome saw 28 emperors of whom only two had a natural death (from the plague). However, there were also 38 usurpers who raised revolts across the Empire, a clear sign that the security of the frontiers was not the only problem within the Roman world. Usurpation attempts were a constant worry for the emperors in this period; it was a too common method of acceding the throne. Successful usurpers were usually either provincial governors, commanders of a large grouping of Roman legions, or prefects of the Praetorian guard, which had control of Rome, where the Imperial palace still lay.

The danger of usurpation was greater following the death of an emperor, when his successor was not accepted by all provinces. Usually the legions acclaimed their own commander as emperor on news of the accession of a less popular man. The acclaimed emperor, usually a provincial governor, would then march to Italy or where the opponent was stationed, in order to contest for the purple. But legionaries disliked fighting against their brothers in arms, so battles between legions rarely transpired. Two main factors decided the success of a usurpation attempt: loyalty of the legionaries, heavily dependent on the amount of booty or monetary prizes promised on victory; and trust of the military abilities of the commander, upon which depended morale. Failure of either part to fulfill one or two of the criteria normally resulted in a mutiny and death at the hands of their own soldiers. Since the emperors had the status quo and political credibility behind them, the usurper had to be a charismatic man to avoid doubts in his ranks and an untimely death. Valerian, who defeated Aemilianus (himself a usurper) is an example of this kind. Other usurpers, like the emperor Philip the Arab, ascended the throne by a planned murder directed at an established sovereign (in his case Gordian III).

However successful, the usurpation procedure always left the new emperor in a somewhat fragile political position, since the throne had been attained by violent means. The danger of another usurper was always present and the first measures taken were inevitably to put trusted men into important commands. Frequently, the emperor embellished his ancestry and his early life in order to enhance his credibility or the right to the throne. Mentions of obscure genealogical relations with previous popular emperors were common, and certainly confused historians. But most of all the usurper manoeuvred to keep his legions happy, since he owed his power to their continued loyalty.