Russian rabbi; born probably at Pinczow, government of Kielce, Poland, about 1630; died at Brest-Litovsk 1714. Löb was on his father's side the grandson of Joel Sirkes and stepson of David ben Samuel ha-Levi, of whom he was also the pupil. He studied besides under Joshua Hö.schel, author of "Maginne Shelomoh," and under Yom-Ṭob Lipmann Heller. He was rabbi successively of Swirz, Galicia (before 1663), Kamorna, Stobnitz, Zamosc (1679-89), Tiktin, Cracow, and finally Brest-Litovsk (1701-14). He was considered by his contemporaries so great a Talmudic authority that in 1669 he was sent with his stepbrother Isaiah ha-Levi to Constantinople to investigate the claims of Shabbethai Ẓebi. His responsa were published later, under the title "Sha'agat Aryeh" (Neuwied, 1736), by his grandson Abraham Nathan Meisels, who added some of his own under the title "Ḳol Shaḥal." Other responsa of Löb's are to be found in the "Shebut Ya'aḳob," No. 107 edited by his grandson, and in "Teshubot Geonim Batra'e," published first in Turkey by the author of "Ma'ane Elihu," and afterward in Prague (1816).