The Breve reprehensorium (1465) is a treatise in favour of the newly converted Christians of Jewish descent. Based on the only known surviving manuscript, this edition and translation is presented together with an introduction examining the historical background of the controversy surrounding the so-called cristianos nuevos or conversos in late medieval Iberia. Unlike the more famous churchmen and scholars of his time, the author of this “Short Reprehension” is so little known that even his name can only be guessed to be Gutierre de Palma. A highly learned and well-connected member of the Toledan elite, he defended the equality of New and Old Christians both with a plethora of established pro-converso arguments and a number of rather original notions, as his treatise goes to show.