aristocratic families it was not unheard of for individuals to have as many as three, of which some might be hereditary and some personal. These surnames were initially characteristic of patrician families, but over time cognomina were also acquired by the plebeians. However, a number of distinguished plebeian gentes, such as the Antonii and the Marii, were never divided into different branches, and in these families cognomina were the exception rather than the rule. Cognomina are known from the beginning of the Republic, but were long regarded as informal names, and omitted from most official records before the second century BC. Later inscriptions commemorating the early centuries of the Republic supply these missing surnames, although the authenticity of some of them has been disputed. Under the Empire, however, the cognomen acquired great importance, and the number of cognomina assumed by the Roman aristocracy multiplied exponentially. Adding to the complexity of aristocratic names was the practice of combining the full nomenclature of both one's paternal and maternal ancestors, resulting in some individuals appearing to have two or more complete names. Duplicative or politically undesirable names might be omitted, while the order of names might be rearranged to emphasize those giving the bearer the greatest prestige. Following the promulgation of the Constitutio Antoniniana in AD 212, granting Roman citizenship to all free men living within the Roman Empire, the praenomen and nomen lost much of their distinguishing function, as all of the newly enfranchised citizens shared the name of Marcus Aurelius. The praenomen and sometimes the nomen gradually disappeared from view, crowded out by other names indicating the bearer's rank and social connections. Surviving inscriptions from the fifth century rarely provide a citizen's full nomenclature. In the final centuries of the Empire, the traditional nomenclature was sometimes replaced by alternate names, known as signa. In the course of the sixth century, as central authority collapsed and Roman institutions disappeared, the complex forms of Roman nomenclature were abandoned altogether, and the people of Italy and western Europe reverted to single names. Modern European nomenclature developed independently of the Roman model during the Middle Ages and the Renaissance. However, many modern names are derived from Roman originals. Tria nomina The three types of names that have come to be regarded as quintessentially Roman were the praenomen, nomen, and cognomen. Together, these were referred to as the tria nomina. Although not all Romans possessed three