In this article, it is analyzed an existent tension between the goal that Nietzsche established in On the Genealogy of Morality and Nietzsche's 'perspectivism' thesis. On one hand, Nietzsche claims that his method will allow him to account the history of moral truly lived. On the other hand, perspectivism implies that the objectivity of knowledge is impossible. I will propose to establish a difference between 'descriptive perspectivism' and 'prescriptive perspectivism' to solve the tension. Finally, I will argue that, to achieve the objectivity proposed by Nietzsche, it is necessary to make a dominant interpretation in which the Will of Power deletes others interpretations.