Yitzhak ha-Sangari

Yitzhak ha-Sangari was the rabbi who purportedly converted the Khazar royalty to Judaism, according to medieval Jewish sources.

"[1] In Sefer ha-Emunot ("Book of Beliefs"; early 15th century), Rabbi Shem Tov ibn Shem Tov wrote: I have been preceded by Rabbi Yitzhak ha-Sangeri, companion [haver] to the king of the Khazars, who converted through that sage a number of years ago in Turgema [land of Togarmah, i.e. the Turks], as is known from several books.

The [rabbinic] responsa and the valuable and wise sayings of this sage, which show his wisdom in Torah and Kabbalah and other fields are scattered in [different books] in Arabic.

The sage Rabbi Yehuda Halevi, the poet, of Spain, found them and put them into his book, in Arabic, and it has been translated into our language [Hebrew]...Shem Tov's work was cited by Judah Moscato in his work Kol Yehuda.

D. M. Dunlop tentatively identified him with the region of Sangaros, in western Anatolia (not far from the ancient site of Troy).

Cover of the 1880 Hebrew language Warsaw edition of the Kuzari . Although the rabbi in the Kuzari is not named, the cover makes reference to Yitzhak ha-Sangari.