Roman Military Diploma - History

History

Diplomas were issued during the Principate period (52-284 AD) to retiring veterans who had served in those corps of the Roman armed forces which enlisted peregrini, that is, inhabitants of the Roman empire who were not Roman citizens (the vast majority of the empire's population in the 1st and 2nd centuries). Such corps were: the auxilia; Roman navy, the Praetorian Guard's cavalry (equites singulares Augusti); and the cohortes urbanae (the City of Rome's public-order battalions).

The first known diploma dates from AD 52, under emperor Claudius (r. 41-54), who appears to have regularised the practice of granting Roman citizenship to non-citizen auxiliaries after 25 years' service (26 in the navy).

Diplomas were not normally issued to discharged legionaries, as the legions recruited Roman citizens only. However, legionary diplomas were exceptionally issued after the Civil War of 68/69 AD. As an emergency measure, 2 new legions, the I and II Classica (later reconstituted and renamed as I and II Adiutrix, respectively) were formed mainly from naval marines, many of whom did not hold citizenship. At the end of the crisis, these were all awarded Roman citizenship.

In 212, the Constitutio Antoniniana, issued by the emperor Caracalla, granted Roman citizenship to all the inhabitants of the empire, thus ending the second-class peregrini status. This made military diplomas largely redundant, and indeed the last known auxiliary diplomas date from AD 203. But diplomas for service in the navy, Praetorian Guard cavalry and the cohortes urbanae continued to be issued until the late 3rd century. This might be explained by the fact that barbari (foreigners from outside the Roman empire) were still recruited for those units.