were too broad to have stemmed from a single common ancestor, but were instead consistent with separate racial origins. In his Crania Aegyptiaca (1844), Morton analyzed over a hundred intact crania gathered from the Nile Valley, and concluded that the ancient Egyptians were racially akin to Europeans. His conclusions would establish the foundation for the American School of anthropology, and would also influence proponents of polygenism. Development of the Hamitic hypothesis In his influential The Mediterranean Race (1901), the anthropologist Giuseppe Sergi argued that the Mediterranean race had likely originated from a common ancestral stock that evolved in the Sahara region in Africa, and which later spread from there to populate North Africa, the Horn of Africa, and the circum-Mediterranean region. According to Sergi, the Hamites themselves constituted a Mediterranean variety, and one situated close to the cradle of the stock. He added that the Mediterranean race "in its external characters is a brown human variety, neither white nor negroid, but pure in its elements, that is to say not a product of the mixture of Whites with Negroes or negroid peoples." Sergi explained this taxonomy as inspired by an understanding of "the morphology of the skull as revealing those internal physical characters of human stocks which remain constant through long ages and at far remote spots[...] As a zoologist can recognise the character of an animal species or variety belonging to any region of the globe or any period of time, so also should an anthropologist if he follows the same method of investigating the morphological characters of the skull[...] This method has guided me in my investigations into the present problem and has given me unexpected results which were often afterwards confirmed by archaeology or history." The Hamitic hypothesis reached its apogee in the work of C. G. Seligman, who argued in his book The Races of Africa (1930) that: Seligman asserted that the Negro race was essentially static and agricultural, and that the wandering "pastoral Hamitic" had introduced most of the advanced features found in central African cultures, including metal working, irrigation and complex social structures. Despite criticism, Seligman kept his thesis unchanged in new editions of his book into the 1960s. Hamitic hypotheses operated in West Africa as well, and they changed greatly over time. With the demise of the concept of Hamitic languages, the notion of a definable "Hamite" racial and linguistic entity was heavily