[Verginius Rufus]

Arthur Koestler (1905-1983), a Hungarian Jew, later a naturalized British subject, best known for his novel Darkness at Noon, popularized the notion that Ashkenazi Jews are descended from the Khazars in his book The Thirteenth Tribe. So far DNA testing has found no evidence of Khazar ancestry among Ashkenazi Jews (rather, they are most closely related to Sephardic Jews and to Middle Eastern Jews).

[Tax-chick]

So far DNA testing has found no evidence of Khazar ancestry among Ashkenazi Jews ...

Not a surprise.

Being wrong about this does not make Mr. Koestler wrong about everything.