Hitler did not discover anti-Semitism. Since the Middle Ages, Jews in Europe have faced bigotry and persecution, mostly for religious reasons. Christians saw Judaism as a heresy that needed to be eradicated. Jews were often compelled to convert or were barred from working in those occupations. Religion played a smaller part in the nineteenth century. That had Rega been Theories saying the distinctions between races and peoples have taken their spot. The notion that Jews belonged to a different people than, perhaps, Germans gained traction. And Christians who converted to Judaism were still 'different' due to their bloodline.