Answer: Hitler did not invent the hatred of Jews. Jews in Europe had been victims of discrimination and persecution since the Middle Ages, often for religious reasons. Christians saw the Jewish faith as an aberration that had to be quashed. Jews were sometimes forced to convert or they were not allowed to practise certain professions.
There are countless imaginative explanations for the reasons for Hitler's antisemitism. Hitler is said to be have been ashamed of his partly Jewish roots. Another explanation links his hatred of Jews to trauma caused by a poison gas attack in the First World War. Yet other theories suggest that Hitler had contracted a venereal disease from a Jewish prostitute. There are, however, no facts to support these explanations.