The “luz no usada” that appears in fray Luis de León’s ode A Francisco de Salinas, is one of the most celebrated expressions in all his lyrical production. Usually studied by the critics connected with Genesis’s fiat lux, in this paper we’ll try to supplement this reading with some of the most important facets of the Renaissance light’s poetic, represented by the florentin philosopher Marsilio Ficino, relating this light’s appearance with the poem’ s “música estremada”. To this end, we’ll supported by some of the main Renaissance neoplatonism’s premises.La “luz no usada” que aparece en la oda A Francisco de Salinas, de fray Luis de León es una de las más celebradas expresiones de toda su producción lírica. Normalmente estudiada por la crít...