Who first developed the racist theory of an Aryan Master Race?

Joseph Arthur, Comte de Gobineau (14 July 1816 – 13 October 1882) was a French aristocrat who was best known by his contemporaries as a novelist, poet and travel writer but is today most remembered for developing the theory of the Aryan master race and helping to legitimise racism by scientific racist theory and racial demography. Gobineau was an elitist who, in the immediate aftermath of the Revolutions of 1848, wrote a 1400-page book, An Essay on the Inequality of the Human Races in which he claimed that aristocrats were superior to commoners and that they possessed more Aryan genetic traits because of less inbreeding with inferior races (Alpines and Mediterraneans).

Gobineau's writings were quickly praised by white supremacist, pro-slavery Americans like Josiah C. Nott and Henry Hotze, who translated his book into English but omitted around 1000 pages of the original book, including those parts that negatively described Americans as a racially mixed population. Gobineau's writings were also influential on prominent anti-Semites such as Richard Wagner, the Romanian far-right politician professor A. C. Cuza and leaders of the Nazi Party, who later edited and re-published his work.