This study presents the controversies and debates that took place in Spain during the Golden Age between those who supported the use of Latin in the publications of the time and those who, on the contrary, advocated the use of Castilian. Based on a corpus of Spanish texts from the 15th, 16th and 17th centuries, this study aims to show how the defence of the vernacular language (also known as the vulgar language, or romance), which took place at the expense of Latin and which is clearly visible in these writings, corresponded to the affirmation of a national feeling, that is to say, to the awareness of the existence of a real cultural identity.