Jacob Frank

Jacob Joseph Frank (Hebrew: יעקב פרנק; Polish: Jakub Józef Frank; born Jakub Lejbowicz; 1726 – 10 December 1791) was a Polish-Jewish religious leader who claimed to be the reincarnation of the self-proclaimed messiah Sabbatai Zevi (1626–1676) and also of the biblical patriarch Jacob. The Jewish authorities in Poland excommunicated Frank and his followers due to his heretical doctrines that included deification of himself as a part of a trinity and other controversial concepts such as neo-Carpocratian "purification through transgression".

Frank arguably created a religious movement, now referred to as Frankism, which incorporated aspects of Christianity and Judaism. The development of Frankism was one of the consequences of the messianic movement of Sabbatai Zevi. This religious mysticism followed socioeconomic changes among the Jews of Poland, Lithuania and Ruthenia.