> Koestler’s claim that all or most Khazars became Jews is false.
That’s correct, and that’s what I’m saying — the idea that European Jewry has *no* Middle Eastern roots is Koestler’s real underlying bias.
Conversion to Judaism has been rare, but obviously has happened.
That “khazaria” site is an ethnocentric agitprop site — “Over a thousand years ago, the far east of Europe was ruled by Jewish kings who presided over numerous tribes, including their own tribe: the Turkic Khazars.”