Racism dates as far back as the mature period of 2600–1900 BCE during the Indus Valley Civilization, which centered mostly in the western part of the Indian subcontinent. According to the Indo-Aryan migrations theory, Indo-Aryans migrated from Central Asia to India sometime after the collapse of the Indus Valley Civilization. Following the discovery of the Indo-European languages in the 19th century, British historians put forth the Aryan invasion theory which argued that it was "Aryans" who established the caste system, an elitist form of social organization that (according to the British) separated the "light-skinned" Indo-Aryan conquerors from the "conquered dark-skinned" indigenous Dravidian tribes through enforcement of "racial endogamy". This claim was used by the British, defining themselves as "purely Aryan", to justify British Rule in India. Much of this was simply conjecture, fueled by British imperialism. This shows the practice of racial segregation during the Antiquity times.
Middle Ages and the Renaissance
Richard E. Nisbett, a professor of social psychology, has said that the question of racial superiority may go back at least a thousand years, to the time when the Umayyad Caliphate invaded Hispania, occupying most of the Iberian Peninsula for six centuries, where they founded the advanced civilization of Al-Andalus (711-1492). Al-Andalus coincided with La Convivencia, an era of religious tolerance, and with the Golden age of Jewish culture in Iberia (912, the rule of Abd-ar-Rahman III - 1066, Granada massacre). It was followed by a violent Reconquista under the Reyes Catolicos (Catholic Kings), Ferdinand V and Isabella I. The Catholic Spaniards then created the Cleanliness of blood policy. It was during this time in history that the Western concept of aristocratic "blue blood" emerged in a highly racial and implicitly white supremacist context, as author Robert Lacey explains:
It was the Spaniards who gave the world the notion that an aristocrat's blood is not red but blue. The Spanish nobility started taking shape around the ninth century in classic military fashion, occupying land as warriors on horseback. They were to continue the process for more than five hundred years, clawing back sections of the peninsula from its Moorish occupiers, and a nobleman demonstrated his pedigree by holding up his sword arm to display the filigree of blue-blooded veins beneath his pale skin--proof that his birth had not been contaminated by the dark-skinned enemy. Sangre azul, blue blood, was thus a euphemism for being a white man--Spain's own particular reminder that the refined footsteps of the aristocracy through history carry the rather less refined spoor of racism.
Japan proposed racial equality at the Paris Peace Conference in 1919. A large majority supported the Japanese racial equality proposal, however a few countries’ strong oppositions declined it.
Burma, China, India and Japan held Greater East Asia Conference in 1943. The conference declared working for the abolition of racial discrimination. Imperial Japanese Army general Kiichiro Higuchi and colonel Norihiro Yasue saved 20,000 Jews from Germans genocide. Japanese diplomat Chiune Sugihara saved 6,000 Jews from Germans genocide. According to Herbert Bix, Racial discrimination against other Asians was habitual in Imperial Japan.
The Nazis considered Jews, Gypsies, Poles along with other Slavic people like the Russians, Ukrainians, Czechs and anyone else who was not an "Aryan" according to the contemporary Nazi race terminology to be subhuman (Untermensch). The Nazis reasoned that the Germans, being a super human (Übermenschlich) race, had a biological right to displace, eliminate and enslave inferiors. The Nazis killed approximately 6 million Jews during the Holocaust.
After the war, under the "Big Plan", Generalplan Ost foresaw the eventual expulsion of more than 50 million non-Germanized Slavs of Eastern Europe through forced migration, as well as some of the Balts, beyond the Ural Mountains and into Siberia. In their place, Germans would be settled in an extended "living space" (Lebensraum) of the 1000-Year Empire (Tausendjähriges Reich). Herbert Backe was one of the orchestrators of the Hunger Plan - the plan to starve tens of millions of Slavs in order to ensure steady food supplies for the German people and troops.
Heinrich Himmler speech to about 100 SS Group Leaders in Posen, occupied Poland, 1943:
"What happens to the Russians, what happens to the Czechs, is a matter of utter indifference to me... Whether the other peoples live in comfort or perish of hunger interests me only in so far as we need them as slaves for our culture; apart from that it does not interest me. Whether or not 10,000 Russian women collapse from exhaustion while digging a tank ditch interests me only in so far as the tank ditch is completed for Germany... We Germans, who are the only people in the world who have a decent attitude to animals, will also adopt a decent attitude to these human animals, but it is a crime against our own blood to worry about them and to bring them ideals... I shall speak to you here with all frankness of a very serious subject. We shall now discuss it absolutely openly among ourselves, nevertheless we shall never speak of it in public. I mean the evacuation of the Jews, the extermination of the Jewish race."