Anti-Semitism, which is the hatred of Jewish people, had been common in Europe since the Middle Ages, and was especially strong in the 19th century.
An anti-Semitic movement in Germany in the 1890s failed. In the 1920s, Germany was one of the countries in Europe where Jewish people were free.
German Jewish people:
However, German-Jewish success and wealth made many non-Jewish Germans envious.
In the 1920s and 1930s, so-called 'race scientists' declared that some races, eg German 'Aryans', were a master race, or 'Herrenrasse', and superior to other sub-humans, or 'Untermenschen', such as the Roma gypsies, and black people. Nazi race-scientists said that the Jewish people were an anti-race, or 'Gegenrasse', which means not really human at all.
After the First World War, right-wing politicians looked for a scapegoat to blame for Germany's defeat. Hitler blamed the Jewish people – he said they had stabbed the German army in the back. He believed that the Jewish people had no ambition but greed. He thought that they were selfish and not truly German and saw them as enemies of Germany.