 As Roman institutions vanished, and the distinction between nomen and cognomen ceased to have any practical importance, the complex system of cognomina that developed under the later empire faded away.The people of the western empire reverted to single names, which were indistinguishable from the cognomina that they replaced; many former praenomina and nomina also survived in this way.The proliferation of cognomina in the later centuries of the Empire led some grammarians to classify certain types as "agnomina".