 Jews in Russia have historically constituted a large religious diaspora; the vast territories of the Russian Empire at one time hosted the largest population of Jews in the world.Within these territories the primarily Ashkenazi Jewish communities of many different areas flourished and developed many of modern Judaism's most distinctive theological and cultural traditions, while also facing periods of anti-Semitic discriminatory policies and persecutions.The largest group among Russian Jews are Ashkenazi Jews, but the community also includes a significant proportion of other non-Ashkenazi from other Jewish diaspora including Mountain Jews, Sephardic Jews, Crimean Karaites, Krymchaks, Bukharan Jews, and Georgian Jews.