 The question of how to classify different cognomina led the grammarians of the fourth and fifth centuries to designate some of them as "agnomina".For most of the Republic, the usual manner of distinguishing individuals was through the binomial form of praenomen and nomen.But as the praenomen lost its value as a distinguishing name, and gradually faded into obscurity, its former role was assumed by the versatile cognomen, and the typical manner of identifying individuals came to be by nomen and cognomen; essentially one form of binomial nomenclature was replaced by another, over the course of several centuries.