
Judah Leib "Leopold" Löw (Hebrew:יהודה לייב לעף,Hungarian:Lőw Lipót; 22 May 1811 – 13 October 1875) was aHungarianrabbi, regarded as the most important figure ofNeolog Judaism.

Löw was born to the only Jewish family in the villageČerná Hora,Moravia, then part of theAustria. His Jewish name, as appears in all his rabbinical correspondence, was Judah Leib. On his father's side, he was descended from theMaharal of Prague, and on his mother's fromMenachem Mendel Krochmal.[1][2] He received his preliminary education at theyeshivot ofTřebíč,Kolín,Lipník nad Bečvou andEisenstadt (1824 – 35), and then studied philology, pedagogics, and Christian theology at the Lyceum ofBratislava and at the universities ofPest andVienna (1835 – 41). After having been a teacher atProstějov, he succeeded to the rabbinate ofNagykanizsa (10 September 1841).
Löw early in his career acquired a knowledge ofHungarian, and was the first to introduce it into the synagogue service, his firstsermon in that language being printed in 1845. In 1844 he began his literary activity on behalf of the emancipation of the Hungarian Jews, taking the lead in that struggle until its object was attained (1867). The periodicalBen Chananja, edited by him from 1858 to 1867, was an especially influential factor in this movement.
In 1846 Löw had been called toPápa, where he encountered many difficulties. After the revolution he was denounced by his enemies, and was arrested, but was pardoned by GeneralJulius Jacob von Haynau on 14 December 1849 and liberated after two months' imprisonment. In consequence of this persecution he accepted a call toSzeged, where he was installed on 10 December 1850. He refused subsequent calls toLemberg,Brno, andBucharest, as well as to theHochschule für die Wissenschaft des Judenthums at Berlin.
He died atSzeged,Austria-Hungary.
Löw brought his thorough knowledge of history, theology, and esthetics to bear upon the reform of the ritual in agreement with modern views. He was the foremost preacher ofHungary, especially in the vernacular, and was invited to participate in nearly all the patriotic celebrations and synagogal dedications. HisHungarian sermons (1870) formed the first Jewish collection of the kind issued in that language. Löw combined the careful, logical arrangement of the Christian sermon with a clever analysis of complicated haggadic sentences. His studies, beginning with the history of theHalakhah, subsequently included the entire Jewish archeology of post-Talmudic time. He endeavored to determine the development of Jewish life and law as it appears in thehalakhic literature, and to disprove, in the interest ofJudaism, the view that Judaism remained stationary in its manners and customs down to the beginning of theGerman Reformation. His most important archaeological studies and responsa were written for the purpose of proving the development of various institutions and of showing the influence, in many cases, of foreign customs.
Löw was a leading authority both from a scientific point of view and in questions of practical theology. The absolute (1850 – 66) as well as the constitutional government (1867) ofAustria and especially that of Hungary were guided by the replies he gave to their questions in matters referring to the organization of the Jewish ritual and schools. Jewish education throughout Hungary owed much to him. Down to his death he was the leader of the progressive Hungarian Jews, especially after the General Congress — which was convened against his advice and in which he did not take part — had resulted in aschism among the Jews of Hungary instead of the union that had been anticipated.
Aside from his works on the Halakhah, Löw left only one other larger work,Ha-Mafteaḥ (1855), a history (in German) of exegesis among the Jews:[3] this remained authoritative into the twentieth century. After the emancipation, when he gave up the editorship ofBen Chananja, he devoted himself to larger archeological monographs, of which the following were published:Die Graphischen Requisiten (1870 – 71) andDie Lebensalter in der jüdischen Literatur (1875). Fragments of a third volume,Der Synagogale Ritus, were published posthumously (1884). His smaller works have appeared in five volumes (Szeged, 1889 – 1900), the last of which contains a complete bibliography of his works.