The island of Ireland was never conquered by the Roman Empire and this fact is largely responsible for so many of the cultural idiosyncrasies of early medieval Ireland (600- 1200). The widespread use of the vernacular in medieval Irish written sources is particularly remarkable. The Irish showed a pride and an interest in their native language which was unique in western Europe. Such cultural confidence, especially given the dominance of Latin at the period, betrays a strong sense of linguistic identity. The present article examines this question with reference to the advent of literacy, the adaptation of Latin grammatical theory to the vernacular and language origin legends.FRE: L'Irlande n'a jamais été conquise par l'Empire romain ; ceci ...