I have the book by Arthur Koestler "The Thirteenth Tribe." The book's big weak point
is he overdoes his case making Germanic Jewry wiped out basically on the idea that if
you don't hear of a Jewish community in a Germanic country or of it being big it must
have been insignificant in population and so everybody gets wiped out in the
Crusades except for a minority that is so cultured the converted Khazars are so
impressed they give up their language except for the Karaites.
Naturally the Karaites were outside of the Jewish community and whoever wanted to join
up with a converted Turkish branch would have a place to stay but even with the Eastern
European plain "Turkish" and/or Khazar Nonethnically Jewish Karaites
called the Karaims, Turkish origins were magnified to avoid AntiSemitism.
The (converted) Khazars were a people who had eventually a nicely strengthened
religiously Jewish population. But it also had Jews including Khazarian Jews who
were not Jewish through their ancestors being converts, and it also had pagans and
Christians and Muslims. Also Eastern Europe had Jews before the arrival of the
Khazars. The Khazars were considered quite cultured after awhile. They didn't need
German or Yiddish to look sophisticated and also many were forced to convert after
the fall of their countryand also some even went as far as Spain. They certainly made a
contribution to at least a part of Eastern Europe's Jewish population but did not
comprise the basic element as claimed by Koestler. There was indeed a Muscovite
Judaizing movement started by two preists who left Christianity and there were
always converts to Judaism despite the risk of death for doing so.
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