or MAMERCUS, the most ancient family of the patrician Aemilia Gens, and one of the most distinguished of all the Roman families in the early ages of the republic. The family professed to derive its name from Mamercus in the reign of Numa, to whom indeed all the Aemilii traced their origin. [MAMERCUS; AEMILIA GENS.] This family, like many of the other distinguished families in early Roman history, disappears about the time of the Samnite wars. The name Mamercus was very early used as a praenomen in the Aemilia gens, and continued to be so employed, especially by the Aemilii Lepidi, long after the family of this name had become extinct. In the same way we find that Cossus, which was originally a family-name of the Cornelii, was revived as a praenomen by the Cornelii Lentuli, after the family of the Cossi had sunk into oblivion. [COSSUS.]