The history of the Krymchaks is inseparably linked with the history of the Jewish communities in the Crimea who had settled there no later than the last centuries B.C. The formation of the Krymchaks as a separate Jewish ethnic group, however, goes back only to the Middle Ages. Although the process intensified between the fourteenth and sixteenth centuries, it was completed only in the nineteenth century. Between the fourteenth and eighteenth centuries, the Jewish population in the Crimea was replenished with a rather significant number of immigrants from the Mediterranean countries, eastern Europe, and also from the Caucasus and Persia, who were incorporated into the already existing Jewish communities. One of the most important steps in the formation of the Krymchaks was their transition to the Crimean Tatar language, which apparently took place between the ends of the fourteenth and sixteenth centuries. Another important step in the formation of the new Jewish group was the religious and cultural consolidation of Crimean Jewry that took place at the turn of the fifteenth and sixteenth centuries. To a large extent it was connected with activities of Rabbi Moshe ben Yaakov (Moshe ha-Gola; 1448-1520). The third and final crucial step in the Krymchak ethnogenesis was the formation of the Karasubazar community, which probably took place between the seventeenth and eighteenth centuries (perhaps even a little earlier). Presumably, between the sixteenth and seventeenth centuries this community began to see itself as a separate group, especially in regard to Jewish newcomers who continued to immigrate to the Crimea. After the Russian conquest of the Crimea in 1783 the Krymchaks and all other Jews were affected by the Russian Empire's discriminatory legislation, which was abolished only after the February Revolution of 1917. In the period between the two world wars, the acculturation of the Krymchaks and their linguistic Russification had already been in progress. The Krymchaks' schools and other cultural and religious institutions were closed by the Soviet authorities in the beginning of the 1930s. During the German occupation of the Crimea, the Krymchaks were killed, one and all, except for those who served at the front in the Red Army or had been evacuated to nonoccupied territories. The trauma of the Holocaust and the growing state and public anti-Semitism in the postwar Soviet Union resulted in further intensification of the processes of acculturation and assimilation.
Before the Revolution of 1917 the Krymchaks always considered themselves true Orthodox Jews, although different from the Ashkenazim, and they were also seen as such by other Jewish communities. Up to the period before World War I, the Sephardim of Turkey served the Krymchaks as a reference group of higher status and provided an authoritative religious tradition. The Krymchak attitude toward the Ashkenazim settling in the Crimea was more ambivalent. In daily life, the Krymchaks sometimes had negative attitudes toward them; however, they admitted that the Ashkenazi Jews were more cultured and educated. In the past many Krymchaks knew Yiddish, and even now one meets some Krymchak elders who understand it or even speak it. In the cities where the Krymchaks lacked communities of their own, they joined communities of the Ashkenazi Jews and attended their synagogues. Intermarriage with Ashkenazim, although not very frequent before the Revolution or even before World War II, nevertheless did occur. On the other hand, before the Russian conquest of the Crimea, and also during the nineteenth and the first decades of the twentieth centuries, the material culture of the Krymchaks was similar to that of the Crimean Tatars. The Tatar influence appreciably affected Krymchak housing patterns, interior decoration and appointments, garments, cuisine, and many other elements of their culture. At present their culture differs little from the cultures of the peoples among whom they live, especially the Russians.