Jacob Frank (1726 – December 10th, 1791) was an 18th-century Jewish religious leader who claimed to be the reincarnation of the self-proclaimed ‘messiah’ Sabbatai Zevi and also of the biblical patriarch Jacob. Born Jakub Lejbowicz to a Jewish family in Korołówka, in Podolia of Eastern Poland (now in Ukraine), in about 1726. His father was a Sabbatean, and moved to Czernowitz, in the Carpathian region of Bukovina in 1730, where the Sabbatean influence at the time was strong. In the early 1750s Frank formed a network between the Donme in Ottoman territories and Sabbatean followers in in Podolia using the guise of a traveling merchant or preacher as cover. Like Zevi almost a century before the Jewish community made a very public show of disassociating themselves from Frank and his followers (excommunicated). Then just as Zevi and his followers had infiltrated Islamic territory, in 1759 so called ‘Frankists’ (followers of Frank) would to be baptised into the Roman Catholic Church. Frank himself was baptized in Lwów on September 17th, that year. Nevertheless, just as the Donmè secretly continuing Jewish observances, the Frankists continued to be viewed with suspicion due to their strange doctrines. Frank was arrested in Warsaw on February 6th, 1760 and delivered to the Church’s tribunal on the charge of heresy. He was convicted of teaching heresy, and imprisoned in the monastery of Częstochowa.