ABSTRACT
The late-Roman army was shaped, like all the institutions of the Late Empire, by the reforms of Diocletian and Constantine; but they only completed a process that began in the second century, when the unwarlike Marcus Aurelius was forced to take personal command, to improvise field armies and promote able officers unconventionally, and to raise two new legions, because of the crisis on the frontiers. The first soldiers' emperor, Septimius Severus, despite having seen no active service until his proclamation by the Danubian legions, had a clear grasp of military needs and realities. Soldiers' marriages were legally recognized, their pay and privileges were increased, promotion was made easier into posts traditionally held by the upper classes. Severus also increased the legionary army by one-tenth, by raising three Parthica legions commanded, not by senatorial legates, but like the Egyptian legion by experienced officers who had already twice been a legion's leading centurion. One of these legions, the Second, was not committed to frontier defence, but was stationed near Rome, where the old Praetorian Guard was replaced by ten new cohorts of double strength recruited from legionaries. These elite forces, equivalent to three legions, with the help of cavalry that included Moors and guardsmen seconded from provincial alae, were the ancestors of the fourth-century comitatenses: a strategic reserve with which the emperor could reinforce the frontier armies — or curb them if they rebelled.
