Jacob Frank

Jacob Frank (Yaakov Leibovich, 1726-1791) was the founder of Frankism — the most radical and antinomian outgrowth of Sabbateanism. Born in Podolia, he declared himself the reincarnation of Shabbetai Tzvi (and the messiah's 'living God' presence in the world) in the 1750s and gathered a substantial Polish-Jewish following — perhaps as many as 24,000 adherents at peak. The Frankist movement preached deliberate inversion of Torah commandments as the redemptive 'sanctification through transgression'.

Under intense Catholic Church pressure he led roughly 3,000 of his Polish followers in a mass conversion to Christianity in 1759 in Lwów — Polish noble families with Frankist-Converso ancestry (notably the descendants of his daughter Eva Frank in Vienna) are documented for generations. His writings (Words of the Lord) are among the strangest documents in Jewish religious history. He died in Offenbach, Germany in 1791. Frankism's collapse marked the definitive end of the Sabbatean movement as an organized force, though crypto-Frankist families persisted into the modern era.