- Ashkenazi Jews (/ˌɑːʃkəˈnɑːzi, ˌæʃ-/ A(H)SH-kə-NAH-zee; also known as Ashkenazic Jews, Ashkenazis, or Ashkenazim) form a distinct ethnicity of the Jewish diaspora, emerging from the Jewish communities that consolidated during the 10th century in the Rhineland (western Germany) and in Northern France, having migrated there from centers such as Italy and the Middle East. They later began a gradual eastward migration due to the Crusades (11th-13th centuries), and mounting restrictions within the Holy Roman Empire. Particularly following the persecution during the Black Death in the 14th century, the bulk of the Ashkenazi Jews then migrated to the Kingdom of Poland, at the encouragement of Casimir III the Great and his successors, making Poland the main center of Ashkenazi Jewry until the Holocaust.