A military diploma is the modern name of Roman documents confirming the release from the army and the granting of Roman citizenship to a veteran of auxiliary units by the emperor. It existed as a reward for faithful service. The diploma was drawn up by imperial officials and displayed to the public in Rome.
The soldier received it in the form of two bronze plates, which were notarized with a copy of the original constitutionis (imperial edict). The first diplomas were awarded to soldiers who enlisted in the army and served Rome well. This facilitated the romanization of the conquered territories and encouraged more people to join the army. The first diplomas were awarded during the principate’s times. In 212 CE Constitutio Antoniniana granted citizenship to the free inhabitants of the Empire. Thus, issuing new documents for most veterans was unnecessary.
Until the end of the 3rd century CE, a diploma was still issued for veterans of the fleet, Praetorian Guard and cohortum urbanarum. In the 4th century, Rome issued similar documents granting veteran rights, but not related to civil rights. At least a thousand diplomas have survived to our times, but most of them are in fragments. Roman military diplomas are today a valuable historical resource about the Roman Empire, its army and navy.
