POPPERS (Popers), JACOB BEN BENJAMIN HAKOHEN (d. 1740), German rabbi. Born in Prague, Poppers studied under his father and in various yeshivot. He was subsequently appointed rabbi of Coblenz and of Trier, in the Rhineland. He declined an invitation to Halberstadt in 1718 but accepted the rabbinate of Frankfurt where he headed a large yeshivah. His disciples included Jacob Berlin, Joseph *Steinhardt, and Joseph Wassertrilling. Poppers corresponded with the great scholars of his time on halakhic and contemporary problems. He was among those who imposed a ban on Moses Hayyim *Luzzatto in 1725 for teaching Kabbalah and on suspicion that he adhered to the Shabbatean doctrine. Compelled to leave Italy, Luzzatto arrived in Frankfurt, where he was summoned before the bet din of Poppers and, after much discussion, was obliged again to promise not to teach Kabbalah nor to engage in its study until he was 40 years old. Poppers was the author of Shav Ya'akov (Frankfurt, 1741–42), responsa in two parts. Some of his novellae are included in Minḥat Kohen (Fuerth, 1741) by Shabbetai b. Moses. Poppers died in Frankfurt.
M. Horovitz, Frankfurter Rabbinen (19692), 117–24.