Abstract: This article offers a reflection on the parallel diffusion of two complementary versions of Alfonso de Cartagena’s genealogy of kings. The author wrote his text in Latin; eight years later, two of his friends provided a Castilian version accompanied with glosses. The target readership was no longer the same, and neither was the conception of the work: the bishop wanted to combine text with illustrations of the different sovereigns. How much of this remains in the translation?