Racism is the belief that people can be divided into separate groups, or races, based on physical characteristics. According to racist theory, these differences determine the individuals' behavior, abilities, and qualities, and therefore people should be treated according to their "race." These  ideas superimposed the conclusion that some races are superior to others, and that race mixing will have damaging consequences.

Toward the end of the 18th century German scholar Johann Friedrich Blumenbach developed a physiological chart grouping human beings into five races: the White, the Yellow, the Brown, the Black, and the Red. This classification remained dominant in European anthropology well into the 20th century.