Arthur Koestler

The Thirteenth Tribe (1976) is a book by Arthur Koestler(a Hungarian jew).

It advances the controversial thesis that North/East European Jews and their descendants, or Ashkenazim, are not descended from the Israelites of antiquity, but from a group of Khazars, a people originating in the Caucasus region (historical Khazaria) who converted to Judaism in the 8th century and were later forced to move westwards into current Eastern Europe (Russia, Hungary, Ukraine, Poland, Belarus, and other places).

Note: In Judaism there is no conversion.

The antique Israelites(Children of Israel) or "Bani Israel" had 12 tribes. This was the entity which recieved most of the prophets from Allah(SWT). Israelites were rewarded with the loving prophet like Musa(PBUH) who neutralized their worst enemy Pharoh but they were utterly stubborn and unthankfull people so Allah sealed their hearts. They became worst enemies of prophet Isa(PBUH) and prophet Muhammad(PBUH) .

The Europian Jews are also interpreted as "The Gog and Magog"(Yajuj Majuj) by some Muslim scholars who were kept away by Zulqarnain through a strong wall that was broken latter.