The army of the Severan dynasty

The legions, auxilia and fleets that were instrumental in the upheavals of the 3rd century crisis were in many ways different from the army Augustus had adapted from the civil wars. To begin with, as had been explained before, the legionary core of the army was bigger. 25 Legions at the death of Augustus had grown to (probably) 34 legions in 235. The last four of those legions had been added during the reigns of Septimius and Alexander Severus. The garrison of Italy had been enlarged as well. The Praetorian Guard and the Urban Cohorts had been reinforced and the garrison extended by the addition by, among others, the Mauri, an extra cavalry unit. Most importantly there was now a legion based in Italy itself. II Parthica had been assigned to a new base at Alba Iulia, near Rome. This move by Septimius Severus has been explained as a strengthening of the emperor’s hold on Italy, but more recently interpretation has been put forward. The extension of the Italian troops is the next step in the evolution that started with the campaign armies consisting of vexillationes. From the reign of Severus onwards, there was now a permanent core of an army. Extra vexillations could be added to these units to build a full-scale campaign army, but the repercussions for the border garrisons were much less severe. Although it would be an attractive proposition, there is no evidence for the idea that one or both of the Praetorian fleets were part of this reform. The conditions of service were the other, much more commented reform introduced by Septimius Severus. After a full century since Domitian’s addition of another payday, Severus not only raised the soldier’s salary substantially. On top of that, soldiers now also received pay in kind. Since his reign soldiers were also allowed to formally marry, a complete reversal of the strict rules set by Augustus. His son Caracalla again raised army pay. This development probably came from a wish to improve conditions and the ‘image’ of service to attract more recruits. The enlarged army, which by now overwhelmingly recruited within its own communities, must have had some trouble getting its units up to strength, because Severus also brought in a contrasting measure to attracting more new recruits, vz. keeping serving soldiers under arms for a longer period. It is possible, that this new measure was an adaptation to practicalities. Discharge was namely accorded only every other year. However, it seems more likely that this measure had another reason. Since every time-served auxiliary soldier received citizenship and the army recruited in local communities near garrisons, there were less and less potential recruits for whom army citizenship was a relevant and attractive enticement for service. They qualified for legionary service with its concomitant better conditions of service and status. Therefore, from 207 onwards, auxiliary soldiers had to serve 26 instead of 25 years and naval soldiers had to serve 28 years. The blanket grant citizenship to virtually all inhabitants of the empire through the Constitutio Antoniniana may have been inspired by a will to enlarge the tax base, it had the added effect of finally completely removing the main attraction of auxiliary service. Now that all soldiers were citizens, one of the most important distinctions between the various army units had disappeared. The study of equipment suggests that differences in fighting style were fading away as well. The heavy infantrymen in the legions were becoming more flexible infantry. Or rather, the legions themselves included now both heavy infantry, who could even form phalanxes against cavalry, and light infantry who would skirmish and attack the enemy with missiles from behind a protective screen of their more heavily armored comrades. It is possible that some naval units underwent a similar development. Having served on land for extended periods of time, they may have become a more generic type of auxiliary infantry, another source of manpower in Italy.