In response to my earlier post, reader LeonidG sent me email.

I have heard of Hazars, a long defunct tribes which used to fight with Slavic tribes 1000 years ago. There were also arguments regarding whether they were practicing Judaism and whether they have just accepted the religion or were descendants of one of the Israelite tribes.

He further suggested the following links for research:

http://en.wikipedia.org/wiki/Khazars

http://www.ataturk.com/content/view/90/90/ (look for hazars)

http://www.khazaria.com/

Later on December 10, I followed some of the above links.

One on the http://www.khazaria.com/ web site in particular shows the depth of the controversy. Are Russian Jews Descended from the Khazars?, A Reassessment Based upon the Latest Historical, Archaeological, Linguistic, and Genetic Evidence by Kevin Alan Brook