Italo-Romance presents a complex array of definite articles, proclitically bound and often listed in descriptive grammar as allomorphic forms. In this article we explain the variation in shape of the definite articles in multiple systems without resorting to allomorphy. This includes dialectal forms with ‘unexpected’ gemination before vowel-initial stems (never previously analysed) and indefinite/mass articles. We show that a bisyllabic underlying representation for the definite article is surprisingly uniform across time and space in Italy. Our major claim is that this underlying form and its morphological exponents have remained virtually unchanged since Medieval Italo-Romance and the only important changes have been to the phonological processes that affect its surface realisation. This analysis brings together diachrony, many modern dialects and Standard Italian under a shared, morphologically unified, decompositional analysis that is compatible with Distributed Morphology assumptions.