This paper presents a two-phoneme analysis of Spanish rhotics that explains the restricted nature of the synchronic contrast and its relation to the Latin geminate. It is argued that the intervocalic contrast resulted from an earlier geminate representation through constraint re-ranking, merger avoidance, and Lexicon Optimization. In other words, that the contrast appears only in intervocalic position is not the result of perceptual distinctiveness or of the presence of an underlying geminate, as proposed by some authors (Bonet & Mascaró 1997, Bradley 2006), but of the contextual distribution of the original Latin geminates, combined with degemination and merger avoidance (Hualde 2004). An optimality-theoretic framework allows for the formalization of the historical developments that led to the current restriction in the distribution of the contrast. In addition to the synchronic contrast, the OT analysis proposed explains the distribution of the rhotic allophones.