In a time of renewed debate  about presentism and the objectivity of historians, the goal of this article is to question the ideological uses and the political functions that the concept of “impartiality” has played in the Spanish Enlightenment, its relation with the writing of history and, more specifically, with the conquest of America. Through a variety of printed texts from the late eighteenth to the early nineteenth-century –apologies, praises, dictionaries and other literary texts– and through a methodology that unites the cultural history and concepts, the focus will be on how the eighteenth-century cultural elites attributed a positive and necessary meaning to the concept to build discourses on what happened in 1492. Dismantling its ideological dimension allows understanding “impartiality” as a constructive tool to “difference”, a notion that legitimates and grants prestige to the Spanish nation as well as structures a complex network of identities.