(ca. 1670–after 1736?), Sabbatian prophet and messianic pretender; central figure in early eighteenth-century Moravian Sabbatianism. Yehudah Leib Prossnitz was born in the southeastern Moravian town of Uherský Brod (Broda), and settled after his marriage in Prossnitz (Prostějov), where his wife’s family lived. Although he was not an educated man, at about age 30 he was drawn to Kabbalah, possibly under the influence of traveling Sabbatian prophets and preachers who visited Moravia at that time, such as Yehoshu‘a Heshel Tsoref, Yehudah Ḥasid, and Ḥayim Malakh. He adopted the ascetic life they preached, began to study the Zohar and other kabbalistic texts, and claimed to receive otherworldly instruction from the deceased Yitsḥak Luria and Shabetai Tsevi. Yehudah Leib soon acquired the reputation of an inspired kabbalistic preacher, attracting a local following and gaining the support of the local rabbi of Prossnitz, Me’ir Eisenstadt (ca. 1670–1744), who was not unsympathetic to Sabbatianism.
Yehudah Leib encountered opposition following the frustrated expectation of Shabetai Tsevi’s return 40 years after his conversion to Islam, in 1706—a date about which Prossnitz had prophesied, and in preparation for which he intensified his ascetic practices and messianic agitation. He embarked on a series of bizarre magical rituals, designed to subdue the forces of impurity, and promised to bring down and reveal the shekhinah, the female aspect of the godhead. This alienated Eisenstadt, discredited Yehudah Leib, and led to his being banished from Prossnitz and placed under a ban of excommunication. Nevertheless, Yehudah Leib soon returned to Prossnitz, where he led the secret Sabbatians of the town, and where Yonatan Eybeschütz (ca. 1694–1764)—a pupil and adopted son of Me’ir Eisenstadt—was apparently one of the students he instructed in the heretical Sabbatian Kabbalah.
Yehudah Leib’s Sabbatian doctrine must have been radicalized by contact with the apostate Sabbatians of Salonika, whose emissaries visited Moravia. In 1724, he resumed his public appearances, proclaiming himself the messiah of the House of Joseph, and apparently prophesying that Eybeschütz would succeed Shabetai Tsevi. The rabbinic authorities of Moravia excommunicated him again a year later in Nikolsburg (Mikulov), and he reportedly died in Hungary, although the Sabbatian circle he founded in Prossnitz persisted clandestinely throughout the eighteenth century.
Yehudah Leib appears to have left no literary legacy, but in the late 1970s he was identified as the probable author of two anonymous kabbalistic works, Tsadik yesod ‘olam and Raza’ de-atvin gelifin, which had previously been attributed to Luria, without their evident Sabbatian import ever being recognized.
Yehuda Liebes, “Meḥaber sefer Tsadik yesod ‘olam: Ha-Navi ha-shabeta’i R. Lebele Prosnits,” in Sod ha-emunah ha-shabeta’it: Kovets ma’amarim, pp. 70–76 (Jerusalem, 1995), also in Da‘at 1 (1978): 73–120; Yehuda Liebes, “Sefer Tsadik yesod ‘olam: Mitos shabeta’i,” in Sod ha-emunah ha-shabeta’it: Kovets ma’amarim, pp. 53–69 (Jerusalem, 1995), also in Da‘at 2–3 (1978–1979): 159–173; Gershom Scholem, “Judah Leib Prossnitz,” in Kabbalah, pp. 441–442 (Jerusalem, 1974).