This paper deals with the treatment of the Spanish –ría form by the Renaissance grammarians, on a period which stretches from Nebrija’s Gramática de la lengua castellana (1492) to Villar’s Arte de la lengua castellana (1651). The study is based on an extended corpus which includes, besides the works of the pioneers of the grammatical tradition in Spain (Nebrija, Correas and Villar), a large number of didactic treatises, coming from different countries. Two aspects are examined: i) the categorization of the –ria form as a subjunctive imperfect, i.e the proposition made by Nebrija, and ii) the no-perception of the –ria form as a Future in the Past. We focus on the position occupied by the Spanish grammarians in relation to foreign patterns and on the conceptual obs-tacles that made impossible the perception of the –riaform as a Future in the Past.