A suitable space to analyse the concepts of author and authorship, the florilegium arises around the notion of "auctoritas" because it is a selection and compilation of passages of diverse authors or only of one author. In addition, the "compilator" is at the same time "auctor" of the florilegium, considering that he modifies the selected texts according to his purposes. The "Floresta de philosophos" is a Castilian florilegium, which is in debt with classical authors, mainly with Seneca, but also with medieval authors, as Boethius or St. Bernard. One of its particularities is the omission of the non-classical, intermediary sources, i.e., Nicolas Trevet in the case of Boethius or Leonardo Bruni in the case of Plato, for instance. In this work we will attend to the concepts or "auctor" and "auctoritas" in the "Floresta". Moreover, we will present de real sources -hidden or not- of this work.Depto. de Filología ClásicaFac. de FilologíaTRUEMinisterio de Ciencia e Innovación (MICINN)Ministerio de Educaciónpu