[8] They traditionally speak Yiddish,[8] a language that originated in the 9th century,[9] and largely migrated towards northern and eastern Europe during the late Middle Ages due to persecution.

[18] The Ashkenazi population was significantly diminished by the Holocaust carried out by Nazi Germany during World War II, which killed some six million Jews, affecting practically every European Jewish family.

[38] His contemporary Saadia Gaon identified Ashkenaz with the Saquliba or Slavic territories,[39] and such usage covered also the lands of tribes neighboring the Slavs, and Eastern and Central Europe.

Thus the prayer-book of Isaiah Horowitz, and many others, give the piyyutim according to the Minhag of Ashkenaz and Poland.Like other Jewish ethnic groups, the Ashkenazi originate from the Israelites[45][46][47] and Hebrews[48][49] of historical Israel and Judah.

[citation needed] In 63 BCE, the Siege of Jerusalem saw the Roman Republic conquer Judea, and thousands of Jewish prisoners of war were brought to Rome as slaves.

[69][better source needed] Sporadic[70] epigraphic evidence in gravesite excavations, particularly in Brigetio (Szőny), Aquincum (Óbuda), Intercisa (Dunaújváros), Triccinae (Sárvár), Savaria (Szombathely), Sopianae (Pécs) in Hungary, and Mursa (Osijek) in Croatia, attest to the presence of Jews after the 2nd and 3rd centuries where Roman garrisons were established.

The excavations suggest they first lived in isolated enclaves attached to Roman legion camps and intermarried with other similar oriental families within the military orders of the region.

[70] Raphael Patai states that later Roman writers remarked that they differed little in either customs, manner of writing, or names from the people among whom they dwelt; and it was especially difficult to differentiate Jews from the Syrians.

[72][31] After Pannonia was ceded to the Huns in 433, the garrison populations were withdrawn to Italy, and only a few, enigmatic traces remain of a possible Jewish presence in the area some centuries later.

In Gaul and Germany itself, with the possible exception of Trier and Cologne, the archeological evidence suggests at most a fleeting presence of very few Jews, primarily itinerant traders or artisans.

By the 11th century, Jewish settlers moving from southern European and Middle Eastern centers (such as Babylonian Jews[86] and Persian Jews[87]) and Maghrebi Jewish traders from North Africa who had contacts with their Ashkenazi brethren and had visited each other from time to time in each's domain[88] 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.

[89] 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.

So when the knights of the First Crusade came to siege Jerusalem, one of Dolberger's family members who was among them rescued Jews in Palestine and carried them back to Worms to repay the favor.

[91] In the 11th century, the "Rabbinic mode of thought and life" and the culture of the Babylonian Talmud that underlies it became established in southern Italy and then spread north to Ashkenaz.

Furthermore, Jews lived almost exclusively in shtetls, maintained a strong system of education for males, heeded rabbinic leadership, and had a very different lifestyle to that of their neighbours; all of these tendencies increased with every outbreak of antisemitism.

[102][103][104][105] Material relating to the history of German Jews has been preserved in the communal accounts of certain communities on the Rhine, a Memorbuch, and a Liebesbrief, documents that are now part of the Sassoon Collection.

In an essay on Sephardi Jewry, Daniel Elazar at the Jerusalem Center for Public Affairs[107] summarized the demographic history of Ashkenazi Jews in the last thousand years.

Disabilities that had limited the rights of Jews since the Middle Ages were abolished, including the requirements to wear distinctive clothing, pay special taxes, and live in ghettos isolated from non-Jewish communities and the prohibitions on certain professions.

In North American cities, social trends such as the chavurah movement, and the emergence of "post-denominational Judaism"[133][134] often bring together younger Jews of diverse ethnic backgrounds.

But with modernization, Yiddishkeit now encompasses not just Orthodoxy and Hasidism, but a broad range of movements, ideologies, practices, and traditions in which Ashkenazi Jews have participated and somehow retained a sense of Jewishness.

For roughly a thousand years, the Ashkenazim were a reproductively isolated population in Europe, despite living in many countries, with little inflow or outflow from migration, conversion, or intermarriage with other groups, including other Jews.

[155] Ashkenazic Jews display the homogeneity of a genetic bottleneck, meaning they descend from a larger population whose numbers were greatly reduced but recovered through a few founding individuals.

Although the Jewish people, in general, were present across a wide geographical area as described, genetic research by Gil Atzmon of the Longevity Genes Project at Albert Einstein College of Medicine suggests "that Ashkenazim branched off from other Jews around the time of the destruction of the First Temple, 2,500 years ago ... flourished during the Roman Empire but then went through a 'severe bottleneck' as they dispersed, reducing a population of several million to just 400 families who left Northern Italy around the year 1000 for Central and eventually Eastern Europe.

[158][159][160] A 2000 study by Hammer et al.[161] found that the Y-chromosome of Ashkenazi and Sephardic Jews contained mutations that are also common among Middle Eastern peoples, but uncommon among indigenous Europeans.

[25] Specifically, although haplogroup K is common throughout western Eurasia, its global distribution makes it very unlikely that "the four aforementioned founder lineages entered the Ashkenazi mtDNA pool via gene flow from a European host population".

The study argued that the great majority of Ashkenazi maternal lineages were not brought from the Near East or the Caucasus, but instead assimilated within Europe, primarily of Italian and Old French origins.

[177] Atzmon's team found that the SNP markers in genetic segments of 3 million DNA letters or longer were 10 times more likely to be identical among Jews than non-Jews.

[181] On the Bray et al. tree, Ashkenazi Jews were found to be a genetically more divergent population than Russians, Orcadians, French, Basques, Sardinians, Italians and Tuscans.

The authors explained that "the most parsimonious explanation for these observations is a common genetic origin, which is consistent with an historical formulation of the Jewish people as descending from ancient Hebrew and Israelite residents of the Levant".

[184] In addition to the genetic contributions from neighboring Europeans, Near Easterners and North Africans, Ashkenazi Jews share some East Eurasian haplogroups, such as N9a, A, and M33c, with Chinese populations.