19th-century racism became closely intertwined with nationalism, leading to the ethnic nationalist discourse that identified the "race" with the "folk", leading to such movements as pan-Germanism, pan-Turkism, pan-Arabism, and pan-Slavism, medieval racism precisely divided the nation into various non-biological "races", which were thought to be the consequence of historical conquests and social conflicts. Michel Foucault traced the genealogy of modern racism to this medieval "historical and political discourse of race struggle". According to him, it divided itself in the 19th century according to two rival lines: on one hand, it was incorporated by racists, biologists and eugenicists, who gave it the modern sense of "race", and they also transformed this popular discourse into a "state racism" (e.g., Nazism). On the other hand, Marxism also seized this discourse founded on the assumption of a political struggle that provided the real engine of history and continued to act underneath the apparent peace. Thus, Marxists transformed the essentialist notion of "race" into the historical notion of "class struggle", defined by socially structured positions: capitalist or proletarian. In The Will to Knowledge (1976), Foucault analyzed another opponent of the "race struggle" discourse: Sigmund Freud's psychoanalysis, which opposed the concept of "blood heredity", prevalent in the 19th century racist discourse. Authors such as Hannah Arendt, in her 1951 book The Origins of Totalitarianism, have said that the racist ideology (popular racism) which developed at the end of the 19th century helped legitimize the imperialist conquests of foreign territories and the atrocities that sometimes accompanied them (such as the Herero and Namaqua Genocide of 1904–1907 or the Armenian genocide of 1915–1917). Rudyard Kipling's poem, The White Man's Burden (1899), is one of the more famous illustrations of the belief in the inherent superiority of the European culture over the rest of the world, though it is also thought to be a satirical appraisal of such imperialism. Racist ideology thus helped legitimize the conquest and incorporation of foreign territories into an empire, which were regarded as a humanitarian obligation partially as a result of these racist beliefs. However, during the 19th century, Western European colonial powers were involved in the suppression of the Arab slave trade in Africa, as well as in the suppression of the slave trade in West Africa. Some Europeans during the time period objected to injustices that occurred in some colonies and lobbied on behalf of aboriginal peoples. Thus, when the Hottentot Venus