Starting with Dante’s Apenninic west-east divide into 14 vulgaria (De vulgari eloquentia 1.x.6-9; cf. Coletti 1995), there is a long tradition in Italian dialectology to classify the dialects by geographical criteria. Putting aside many of the details (see Pellegrini 1975; Bruni 1987:290f.; Cortelazzo 1988; Maiden 1995:233-48; Loporcaro 2009), today the dialects are conventionally, though not uncontroversially, classified according to a north-south axis which, although excluding Sardinian (Bossong 2016:65; Mensching and Remberger 2016:270), recognizes the three broad linguistic areas of the north (cf. Benincà, Parry and Pescarini 2016), centre (cf. Loporcaro and Paciaroni 2016) and south (cf. Ledgeway 2016a), characterized, in turn, by a series of internal subdivisions (e.g. Gallo-Italic vs Venetan northern dialects; Tuscan vs non-Tuscan central dialects; upper vs extreme southern dialects). Variously coinciding with early administrative, political and cultural divisions and, in part, with the distribution of the ancient peoples of the peninsula and their substrate languages (Ascoli 1882; Merlo 1937; 1933), these three macro-areas constitute a geographic continuum with linguistic distance increasing proportionately with geographic distance, allowing us to recognize two principal isoglosses (see Rohlfs [1972]1977; Savoia 1997): the La Spezia–Rimini Line – more accurately a bundle of phonetic and lexical isoglosses running from Carrara to Fano – traditionally delineates northern dialects from those of the centre-south which, in turn, are only more loosely differentiated from each other through the bundles of phonetic, lexical and some morphological isoglosses traditionally grouped together under the Rome-Ancona Line.