 Rashi uses "leshon Ashkenaz" (Ashkenazi language) to describe the German language, and Byzantium and Syrian Jewish letters referred to the Crusaders as Ashkenazim.Given the close links between the Jewish communities of France and Germany following the Carolingian unification, the term Ashkenazi came to refer to both the Jews of medieval Germany and France.Ashkenazi Jewish culture later spread in the 16th Century into Eastern Europe, where their rite replaced that of existing Jewish communities whom some scholars believe to have been larger in demographics than the Ashkenazi Jews themselves, and then to all parts of the world with the migrations of Jews who identified as "Ashkenazi Jews".