1 Two basic facts emerge from our survey: the disappearance of the Khazar nation from its historic habitat, and the simultaneous appearance in adjacent regions to the north-west of the greatest concentration of Jews since the beginnings of the Diaspora.
•    But they feel less certain about the extent of this contribution – the size of the Khazar immigration compared with the influx of Western Jews, and their respective share in the genetic make-up of the modern Jewish community.
•    In other words, the fact that Khazars emigrated in substantial numbers into Poland is established beyond dispute; the question is whether they provided the bulk of the new settlement, or only its hard core, as it were.
•    2 Towards the end of the first millennium, the most important settlements of Western European Jews were in France and the Rhineland.* Some of these communities had probably been founded in Roman days, for, between the destruction of Jerusalem and the decline of the Roman Empire, Jews had settled in many of the greater cities under its rule, and were later on reinforced by immigrants from Italy and North Africa.
•    Thus we have records from the ninth century onwards of Jewish communities in places all over France, from Normandy down to Provence and the Mediterranean.
•    Their history has been summed up by Baron: They were subsequently converted into a class of `royal usurers` whose main function was to provide credits for both political and economic ventures.
•    The meteoric rise, and even more rapid decline of English Jewry in the brief span of two and a quarter centuries (1066–1290) brought into sharp relief the fundamental factors shaping the destinies of all western Jewries in the crucial first half of the second millennium.2 The English example is instructive, because it is exceptionally well documented compared to the early history of the Jewish communities on the Continent.
•    The main lesson we derive from it is that the social-economic influence of the Jews was quite out of proportion with their small numbers.
•    There were, apparently, no more than 2500 Jews in England at any time before their expulsion in 1290.* This tiny Jewish community in mediaeval England played a leading part in the country`s economic Establishment – much more so than its opposite number in Poland; yet in contrast to Poland it could not rely on a network of Jewish small-towns to provide it with a mass-basis of humble craftsmen, of lower-middle-class artisans and workmen, carters and innkeepers; it had no roots in the people.
•    `In the “dark ages”,` wrote Cecil Roth, `the commerce of Western Europe was largely in Jewish hands, not excluding the slave trade, and in the Carolingian cartularies Jew and Merchant are used as almost interchangeable terms.`4 But with the growth of a native mercantile class, they became gradually excluded not only from most productive occupations, but also from the traditional forms of commerce, and virtually the only field left open to them was lending capital on interest.
•    `… The floating wealth of the country was soaked up by the Jews, who were periodically made to disgorge into the exchequer….`5 The archetype of Shylock was established long before Shakespeare`s time.
•    Though later some were allowed to return, they suffered further persecution, and by the end of the century the French community of Jews was virtually extinct.* 2 If we turn to the history of German Jewry, the first fact to note is that `remarkably, we do not possess a comprehensive scholarly history of German Jewry….
•    The Germanica Judaica is merely a good reference work to historic sources shedding light on individual communities up to 1238.`6 It is a dim light, but at least it illuminates the territorial distribution of the Western-Jewish communities in Germany during the critical period when Khazar–Jewish immigration into Poland was approaching its peak.
•    One of the earliest records of such a community in Germany mentions a certain Kalonymous, who, in 906, emigrated with his kinsfolk from Lucca in Italy to Mayence.