Jacob Frank was an 18th-century religious leader born in 1726 in what is now Poland. He is best known for founding the Frankist movement, which emerged from Jewish mysticism and sought to reform traditional Judaism. Frank claimed to be the Messiah and attracted a following by promoting radical ideas that challenged established religious norms. His teachings emphasized the importance of personal experience and direct connection to the divine, often incorporating elements from Christianity and other faiths. Frank's controversial beliefs led to significant opposition from both Jewish authorities and the broader community, resulting in his excommunication and eventual imprisonment.