International audience; Both Modern French quantifiers and the Modern French Determiner Phrase have been the focus of numerous analyses. The current study is a diachronic contribution to this literature, focusing on the development of one universal quantifier—chacun “each”—from 1100 through 1925. Old and Middle French chacun fulfilled a variety of syntactic functions: It was used as a pronoun, a modifier, and was found in emphatic constructions with the indefinite article (un chacun “a each”). By the 16th century, this surface heterogeneity gave way and pronominal chacun dominated. On the basis of the diachronic evidence, I first consider the possibility of extending an existing analysis of a different quantifier, aucun “none, not any,” to chacun. After arguing against this extension, I suggest that, contrary to appearances, a unified syntactic structure underlies the Old and Middle French chacun, and that this single construction gave rise to two modern syntactic structures.