Grammar of dates: Preliminary study to their automatic treatment. The automatic analysis of dates in a text requires a precise description of all the possible forms. This article presents a detailed study of the sentence Ceci est arrivé le jeudi 3 avril 1986 à huit heure cinq (this happened thursday april the third 1986 at five past eight) according to the transformational methods developed by Z.S. Harris and M. Gross. This sentence is considered as derived from a more complete one where genitives have been introduced and whose different steps of derivation are nearly all attested (sometimes in old French). The sentences obtained in this way are analysed either by the replacement of the definite article by another determinant, or by its deletion. For each determinant, an automaton is described which identifies the various attested forms. Finally, the influence on the previous forms of modifiers and conjunctions is studied. There follows a short description of the calendar and the resulting constraints.