The sigmatic anthroponyms Σωκράτης and Ἀριστοφάνης correspond to two quite different kinds of designations : adjectives of the type ἀκρατής, which are early and whose second element is always a noun (κράτος), and those of the type ἀφανής, whose second element is always a verb root (φαν- from φαίνομαι) and which are recent. The article seeks to show that even if adjectives of the second type grew in number to the point where they overtook those of the first type, the opposite is true for anthroponyms : names like Σωκράτης are much commoner than names like Ἀριστοφάνης. This is the result of onomastic conservatism. The article concludes with a case study of the creation of names ending in -χάρης and -φάνης : it appears that the first were created to complement names in Χαρι- and that the second took over from names ending in -φάης.