The studies in this issue of Studi e Saggi Linguistici show how variation and norm did coexist and contrast even in the classical world. The different sections find their pivot on the notion of variation, viewed in its relations with language contact and linguistic identity. Besides Ancient Greek and Latin (Sections I and II), Italic languages as well as other ancient Indo-European languages (Sections III and V) settle the empirical domain. The material investigated ranges from literary texts to tablets, inscriptions and other non-literary texts. The relevant patterns of linguistic variation emerge from an in-depth analysis of graphemic, morpho-phonological, syntactic and lexical markers. The grammatical tradition, especially rich in the case of Greek and Latin, makes up a supplementary as well as strong evidence for the study of linguistic variation (Section IV). We believe that models developed from the description and interpretation of contemporary realities may support the reconstruction of the sociohistorical contexts where ancient languages were used. The study of data derived from written sources may considerably benefit from the integration of the more traditional philological analysis with contemporary sociolinguistics and theoretical linguistics. Such an integrated methodology might even overcome some inconsistency of the textual data available. In our wishes, the collection of studies in this issue of Studi e Saggi Linguistici should represent an adequate example of how modern and ancient notions, both theoretical and methodological, may proceed hand in hand.