They were the original Jews that the Karimi-Karaitizers followed before swapping them for Russian Karaims instead. They were centred on Evpatoria and first appear in the Russian Empire under the Giray treasurer Benjamin Aga who posing only as Karimi-Karaitizers instead of revealing their Jewish identity petitioned Catherine the Great through Count Zubov to exempt his people from the double taxation imposed on the Jews.
In 1919 they evicted the reformer Seraya Shapshal who fled to Austro-Hungarian Serbia then 9 years later led the Polish Karaites.
Tovia Levi-Babovich moved from Crimea to Egypt in 1934 and until his death in 1956 began to formulate what under the influence of Mordechai Alfandari in Israel has now become the heretical sect known as Karaite Judaism. He was not removed by the Nazis because the Nazis did not consider the Karaites to be Jews. In fact some Socialist Ukrainian Nationalist Crimean Karaites collaborated with the Nazis to eliminate the Karaimites who Seraya Shapshal was trying to help.
Simon Szyszman argues strongly that they are Judaizers only and not of any sort of Jewish origin.