names, the practice of using multiple names having different functions was a defining characteristic of Roman culture that distinguished citizens from foreigners. Praenomen The praenomen was a true personal name, chosen by a child's parents, and bestowed on the dies lustricius, or "day of lustration", a ritual purification performed on the eighth day after the birth of a girl, or the ninth day after the birth of a boy. Normally all of the children in a family would have different praenomina. Although there was no law restricting the use of specific praenomina, the choice of the parents was usually governed by custom and family tradition. An eldest son was usually named after his father, and younger sons were named after their father's brothers or other male ancestors. In this way, the same praenomina were passed down in a family from one generation to the next. Not only did this serve to emphasize the continuity of a family across many generations, but the selection of praenomina also distinguished the customs of one gens from another. The patrician gentes in particular tended to limit the number of praenomina that they used far more than the plebeians, which was a way of reinforcing the exclusiveness of their social status. Of course, there were many exceptions to these general practices. A son might be named in honour of one of his maternal relatives, thus bringing a new name into the gens. Because some gentes made regular use of only three or four praenomina, new names might appear whenever a family had more than three or four sons. Furthermore, a number of the oldest and most influential patrician families made a habit of choosing unusual names; in particular the Fabii, Aemilii, Furii, Claudii, Cornelii, and Valerii all used praenomina that were uncommon amongst the patricians, or which had fallen out of general use. In the last two centuries of the Republic, and under the early Empire, it was fashionable for aristocratic families to revive older praenomina. About three dozen Latin praenomina were in use at the beginning of the Republic, although only about eighteen were common. This number fell gradually, until by the first century AD, about a dozen praenomina remained in widespread use, with a handful of others used by particular families. The origin and use of praenomina was a matter of curiosity to the Romans themselves; in De Praenominibus, Probus discusses a number