This essay focuses on the sources for De institutione grammatica libo quinque (1601). This was a new edition of Introductiones Latinae by Nebrija, revised by Father Juan Luis de la Cerda. This latter work was subsequently enforced as the official handbook for the teaching of Latin in learning centres �including universities. The aforesaid works have been exhaustiveliy compared, with the main purpose of identifying those points where Juan Luis de la Cerda departs from Nebrija �as to both theoretical issues and the organization of the work itself. The main reason for these differences are due on the heavy influence on De institutione grammatica libri quinque of two works: Minerva by Sanctius and, aboye all, De institutione grammatica libri tr...