The ongoing evolution of Johann Friedrich Blumenbach’s approach to human variation for the last two centuries can be interpreted through an understanding of race in science as inherently connected with the vicissitudes of the legitimacy of colonial power. In this chapter, a Blumenbachian vision on human perfection is historicized as reproduced in the various stages of colonial power. The circulation of Blumenbach’s perspectives is connected to public and scientific debates regarding slavery and the post-slavery social order. The continuities and changes in Blumenbach’s conceptualization of human perfection during post-slavery colonialism is elaborated through debates on racial intermixture as either a progressive or a dystopian scenario for humanity. The controversies between James Cowles Prichard and Josiah Nott, as well as between Arthur Gobineau and Anténor Firmin, are revised as regards the reproduction of different pathways of racialization. Exploring various methods for visualizing human variation complements the understanding of the longue durée of a Blumenbachian vision on human perfection as a significant diving force in the history of (de)legitimizing colonial power. The conclusion of the chapter problematizes the historicization of race in science and colonial power through the sociological biographies of scientists who have shaped our understanding of human diversity.