 With the Constitutio Antoniniana in 212, the emperor Caracalla granted Roman citizenship to all free inhabitants of the empire.It had long been the expectation that when a non-Roman acquired citizenship he, as part of his enfranchisement, took on a Roman name.With the mass enfranchisement of 212, the new citizens adopted the nomen "Aurelius" in recognition of Caracalla’s beneficence (the emperor's full name was Marcus Aurelius Severus Antoninus Augustus, with Aurelius as the nomen).