back three generations. Cognomen replaces praenomen The praenomen, even under the classic system, had never been particularly distinctive because of the limited number of praenomina available. Between the late Republic and the second century AD, the praenomen gradually became less used and eventually disappeared altogether. Even among the senatorial aristocracy it became a rarity by about 300 AD. In part this came about through a tendency for the same praenomen to be given to all males of a family, thereby fossilizing a particular preaenomen/nomen combination and making the praenomen even less distinctive e.g. all males in the emperor Vespasian's family (including all his sons) had the praenomen/nomen combination Titus Flavius: The cognomen, as in Vespasian's family, then assumed the distinguishing function for individuals; where this happened, the cognomen replaced the praenomen in intimate address. The result was that two names remained in use for formal public address but instead of praenomen + nomen, it became nomen + cognomen. Edict of Caracalla 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). "Aurelius" quickly became the most common nomen in the east and the second most common (after "Julius") in the west. The change in the origins of the new governing elite that assumed control of the empire from the end of the third century can be seen in their names: seven of the eleven emperors between Gallienus and Diocletian (Claudius Gothicus, Quintillus, Probus, Carus, Carinus, Numerian and Maximian) bore the name "Marcus Aurelius" Although praenomina were not adopted by the new citizens, reflecting the pre-existing decline amongst "old" Romans, in the west the new names were formulated on the same basis as the existing Roman practices. In the east, however, the new citizens formulated their names by placing "Aurelius" before versions of their non-Roman given name and a patronymic. Ultimately, the ubiquity of "Aurelius" meant that it could not function as a true distinguishing nomen, and became primarily just a badge of citizenship added to any name. Traditional nomen replaced Although a nomen would long