Ashkenazi Jews ( ASH-, AHSH-kə-NAH-zee), also known as Ashkenazic Jews or, by using the Hebrew plural suffix -im, Ashkenazim ( ASH-, AHSH-kə-NAH-zim; Hebrew: אַשְׁכְּנַזִּים, Ashkenazi Hebrew pronunciation: [ˌaʃkəˈnazim], singular: [ˌaʃkəˈnazi], Modern Hebrew: [aʃkenaˈzim, aʃkenaˈzi]; also יְהוּדֵי אַשְׁכְּנַז Y'hudey Ashkenaz), are a Jewish diaspora population who coalesced in the Holy Roman Empire around the end of the first millennium.
The traditional diaspora language of Ashkenazi Jews is Yiddish (a Germanic language with elements of Hebrew, Aramaic and Slavic languages), developed after they had moved into northern Europe: beginning with Germany and France in the Middle Ages. For centuries they used Hebrew only as a sacred language, until the revival of Hebrew as a common language in Israel. Throughout their time in Europe, Ashkenazim have made many important contributions to its philosophy, scholarship, literature, art, music and science.
The term "Ashkenazi" refers to Jewish settlers who established communities along the Rhine river in Western Germany and in Northern France dating to the Middle Ages. Once there, they adapted traditions carried from Babylon, the Holy Land, and the Western Mediterranean to their new environment. The Ashkenazi religious rite developed in cities such as Mainz, Worms, and Troyes. The eminent French Rishon rabbi Shlomo Itzhaki (Rashi) would have a significant influence on the Jewish religion.
In the late Middle Ages, due to religious persecution, the majority of the Ashkenazi population shifted steadily eastward, moving out of the Holy Roman Empire into the areas later part of the Polish–Lithuanian Commonwealth, comprising parts of present-day Belarus, Latvia, Lithuania, Moldova, Poland, Russia, and Ukraine.
In the course of the late 18th and 19th centuries, those Jews who remained in or returned to the German lands generated a cultural reorientation; under the influence of the Haskalah and the struggle for emancipation, as well as the intellectual and cultural ferment in urban centers, they gradually abandoned the use of Yiddish and adopted German, while developing new forms of Jewish religious life and cultural identity.
The Holocaust of the Second World War decimated the Ashkenazim, affecting almost every Jewish family. It is estimated that in the 11th century Ashkenazi Jews composed three percent of the world's total Jewish population, while an estimate made in 1930 (near the population's peak) had them as 92 percent of the world's Jews. Immediately prior to the Holocaust, the number of Jews in the world stood at approximately 16.7 million. Statistical figures vary for the contemporary demography of Ashkenazi Jews, ranging from 10 million to 11.2 million. Sergio Della Pergola, in a rough calculation of Sephardic and Mizrahi Jews, implies that Ashkenazi Jews make up less than 74% of Jews worldwide. Other estimates place Ashkenazi Jews as making up about 75% of Jews worldwide.
Genetic studies on Ashkenazim—researching both their paternal and maternal lineages—suggest that they are of both Middle Eastern and European descent. These studies have arrived at diverging conclusions regarding both the degree and the sources of their European and Middle Eastern ancestry, with some focusing on the extent of the European genetic origin observed in Ashkenazi maternal lineages. Ashkenazi Jews are popularly contrasted with Sephardi Jews (also called Sephardim), who descend from Jews who settled in the Iberian Peninsula, and Mizrahi Jews, who descend from Jews who remained in the Middle East.