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Protector Augusti Nostri (lit 'Protector of Our Augustus') was a title given to individual officers of the Roman Army as a mark of their devotion to and approval by the Emperor himself. The term first appears with this meaning in the joint-reign of Valerian and Gallienus. L. Petronius Taurus Volusianus was the first recorded Protector appointed by Gallienus.

Imperial Guards of GallienusEdit

It is indeed the case that the use of the title protector in the sense of a 'bodyguard of a Great Man' long preceded the appointment of Volusianus. In addition, the title was not only bestowed by Emperors.[1] However, it does seem to be the case that Gallienus was the originator of the particular body of men, the Protectores Augusti Nostri, with which this page is concerned.

It seems that, when it was first bestowed, this title signified an honour conferred on rather than a function carried out by the recipient. It seems to have been granted to officers who had distinguished themselves serving directly under Gallienus in his wars against barbarian invaders of the Balkan and German provinces and Italy and would-be usurpers in those regions such as Ingenuus and were marked out for accelerated promotion under his patronage. No doubt its utility as an instrument for adding lustre to newly equestrianised military career structure soon became apparent.

The first recipients were Tribunes of the Praetorian Cohorts - such as Volusianus - and equestrian commanders of legions such as Publius Aelius Aelianus. So far as is known it was never bestowed on any officer of senatorial rank - senators were effectively excluded from service in the army soon after the first protectores appeared. Towards the end of Gallienus's reign centurions too were given this title. By this time it was used exclusively to distinguish officers who had served in units associated with Gallienus's Imperial Field Army, the comitatus[2]

Collectively, therefor, the first Protectores might more properly defined as a collegio (i.e. a guild) rather than a military unit serving a specific military purpose. There is contemporary reference to a Princeps Protectorum, but it is likely that this officer's functions related to ceremonial than to leadership in battle.[3] Holding commissioned rank in a unit attached to the comitatus seems to have been the sine qua non of admission to the body. These were men noticed by the Emperor likely to receive accelerated promotion in his service.

The purpose of the Protectores at this time seems to have been two-fold: (i) to encourage a personal loyalty to the Augusti (particularly Gallienus: there is no reason to suppose that Valerian had any real interest in this innovation) among the most energetic and charismatic officers of the Imperial Field Army and thus combat the spirit of military dissent that was tearing the Empire apart at this time; (ii) to promote ambition among the officer cadres of provincial garrisons - which would, of course, serve the same purpose.

After GallienusEdit

After the death of Gallienus the Protectores seem to have evolved into a military unit. It was as commander of this body that the future Emperor Diocletian made his successful bid for the purple in 284 AD, challenging the Praetorian Prefect Aper whose power-base was the Praetorian Guard. However, membership of the corps still seems to have continued to be reserved for young soldiers marked out for rapid promotion. Constantine I was probably a member at the court of Galerius and Ammianus Marcellinus got his first step on the ladder of promotion in this capacity. Thus by that time day it had acquired some of the characteristics of an Imperial staff college.


  1. ^ Mihailov, citing E. Birley, mentions two examples of men with this title, one appointed by a Praetorian Prefect and the other by a senatorial legatus. Mihailov, Georgi (1966). Inscriptiones Graecae in Bulgaria Repertae : 3 1570,. Sophia..
  2. ^ See M. Christol: 'La carrière de Traianus Mucianus et l'origine des protectores: Chiron 7, 1977, pp 393 ff.
  3. ^ One of the first known princeps protectorum was Traianus Mucianus - see Mihailov op.cit.. As far as can be determined that officer had no substantive office when he held the title and Christol (op.cit.) infers that his was a purely nominal posting while he waited for promotion to the rank of primus pilus.

Southern, Pat (2001). The Roman Empire from Severus to Constantine. London: Routledge.