Russian archeologists are saying they have found the capital of the Khazar state. This largely Turkic state was multicultural, but its ruling sept converted to Judaism, which it used as the state religion. If it is borne out, this discovery will shed loads of illumination on Jewish history as well as on early medieval life in the area above the Caspian Sea.
The old thesis that most Ashkenazi European Jews were descended from the Khazars has been disproved by genetic testing (a majority of Ashkenazi men have haplotypes common to Palestinian and Lebanese populations), though some Khazar Jews may have been absorbed into the Ashkenazi community.
I recently enjoyed reading
Michael Chabon’s “Gentlemen of the Road”, much of which is set in the Khazar kingdom, and is part homage to Fritz Leiber’s Fafhrd and the Gray Mouser and part allegory of the modern Middle East.