Ashkenazi Jews, also known as Ashkenazic Jews or simply Ashkenazim (Hebrew: ash@k@'nazi'ym, Ashkenazi Hebrew pronunciation: [,aSk@'nazim], singular: [,aSk@'nazi], Modern Hebrew: [aSkena'zim, aSkena'zi]; also y@hv'dey ash@k@'naz Y'hudey Ashkenaz), are a Jewish diaspora population who coalesced as a distinct community in the Holy Roman Empire around the end of the first millennium. The traditional diaspora language of Ashkenazi Jews is Yiddish (a Germanic language which incorporates several dialects), with Hebrew used only as a sacred language until relatively recently. Throughout their time in Europe, Ashkenazim have made many important contributions to philosophy, scholarship, literature, art, music and science. Ashkenazim originate from the Jews who settled along the Rhine River, in Western Germany and in Northern France.

Historical records show evidence of Jewish communities north of the Alps and Pyrenees as early as the 8th and 9th century. By the 11th century Jewish settlers, moving from southern European and Middle Eastern centers, appear to have begun to settle in the north, especially along the Rhine, often in response to new economic opportunities and at the invitation of local Christian rulers. Thus Baldwin V, Count of Flanders, invited Jacob ben Yekutiel and his fellow Jews to settle in his lands; and soon after the Norman Conquest of England, William the Conqueror likewise extended a welcome to continental Jews to take up residence there. Bishop Rudiger Huzmann called on the Jews of Mainz to relocate to Speyer. In all of these decisions, the idea that Jews had the know-how and capacity to jump-start the economy, improve revenues, and enlarge trade seems to have played a prominent role. Typically Jews relocated close to the markets and churches in town centres, where, though they came under the authority of both royal and ecclesiastical powers, they were accorded administrative autonomy. In the 11th century, both Rabbinic Judaism and the culture of the Babylonian Talmud that underlies it became established in southern Italy and then spread north to Ashkenaz. Numerous massacres of Jews occurred throughout Europe during the Christian Crusades. Inspired by the preaching of a First Crusade, crusader mobs in France and Germany perpetrated the Rhineland massacres of 1096, devastating Jewish communities along the Rhine River, including the SHuM cities of Speyer, Worms, and Mainz. The cluster of cities contain the earliest Jewish settlements north of the Alps, and played a major role in the formation of Ashkenazi Jewish religious tradition, along with Troyes and Sens in France. Nonetheless Jewish life in Germany persisted, while some Ashkenazi Jews joined Sephardic Jewry in Spain. Expulsions from England (1290), France (1394), and parts of Germany (15th century), gradually pushed Ashkenazi Jewry eastward, to Poland (10th century), Lithuania (10th century), and Russia (12th century). Over this period of several hundred years, some have suggested, Jewish economic activity was focused on trade, business management, and financial services, due to several presumed factors: Christian European prohibitions restricting certain activities by Jews, preventing certain financial activities (such as "usurious" loans) between Christians, high rates of literacy, near universal male education, and ability of merchants to rely upon and trust family members living in different regions and countries. By the 15th century, the Ashkenazi Jewish communities in Poland were the largest Jewish communities of the Diaspora. This area, which eventually fell under the domination of Russia, Austria, and Prussia (Germany), would remain the main center of Ashkenazi Jewry until the Holocaust. The answer to why there was so little assimilation of Jews in central and eastern Europe for so long would seem to lie in part in the probability that the alien surroundings in central and eastern Europe were not conducive, though contempt did not prevent some assimilation. Furthermore, Jews lived almost exclusively in shtetls, maintained a strong system of education for males, heeded rabbinic leadership, and scorned the lifestyle of their neighbors; and all of these tendencies increased with every outbreak of antisemitism. CANNOTANSWERAnswer this question using a quote from the following article:

Was there any reason for this?

response to new economic opportunities