ISSERLEIN, ISRAEL BEN PETHAHIAH (1390–1460), the foremost rabbi of Germany in the 15th century. Isserlein was also called, after the towns in which he resided, Israel Marburg and Israel Neustadt, but he was mainly known as "the author of Terumat ha-Deshen," his chief work. Isserlein, the great grandson of *Israel of Krems (author of Haggahot Asheri), was born in Regensburg. His father died when Israel was a youth, so he was educated in Wiener-Neustadt in the home of his mother's brother Aaron Plumel (Blumlein). In 1421 his uncle and mother were killed during the Vienna persecutions. After staying for some time in Italy, Isserlein established his residence in Marburg, Styria. In 1445 he returned to Wiener-Neustadt where he was appointed rabbi and av bet din of the city and neighborhood. Here Isserlein spent the rest of his life, and through him Wiener-Neustadt became a center of study, attracting a large number of students, many of whom later served as rabbis in various communities. Outstanding scholars and communities addressed their problems to him and accepted his decisions. The most important posekim valued his books and highly praised his personality. Moses *Mintz
Isserlein lived a life of piety and asceticism. To some extent he may be regarded as continuing the tradition of the Ḥasidei Ashkenaz of the 13th century. In any case the influence of the Sefer Ḥasidim (see *Judah ha-Ḥasid) is recognizable in many of his rulings. One of his intimate pupils, *Joseph b. Moses, noted down in Leket Yosher (ed. by A. Freimann, 1903–04) Isserlein's daily behavior as well as what the author heard from him in his discourses. Isserlein's most important work is his responsa Terumat ha-Deshen, so called because it contained 354 (the numerical equivalent of דשן) sections. Most of these problems were presented by the author himself in order to investigate, clarify, and give practical halakhic rulings on them. They provide an authentic picture of contemporary Jewish life. In this work Isserlein emerges as an erudite and profound scholar, endowed with a logical mind. He based his decisions on the Talmud and mainly on the works of the French and German scholars. Among Spanish scholars he mentions in particular Isaac *Alfasi and *Maimonides; others, such as *Naḥmanides, he mentions only rarely, and still others, such as Solomon b. Abraham *Adret, not at all. Isserlein sought to restore the study of Talmud and other ancient sources to their former importance, because of a growing tendency to rely mainly upon the posekim. He decided in accordance with the view of the earlier authorities rather than the later. He was not deterred by the authority of *Jacob b. Asher, author of the Turim, when the latter differed from the geonim. Generally speaking, Isserlein adopted a strict line where biblical prohibitions were concerned, but in many matters he inclined toward leniency, particularly in order to establish harmonious relations with the Christians. Of his responsa, which he gave on actual cases, 267 have been preserved and arranged by one of his pupils in a collection, Pesakim u-Khetavim, which was published together with Terumat ha-Deshen (Venice, 1519, and elsewhere). His other works include Be'urim ("expositions") to Rashi's biblical commentary (Venice, 1519, new edition, Jerusalem, 1996); She'arim, on the laws of *issur ve-hetter (published in Jerusalem, 1978), which is mentioned in his Pesakim u-Khetavim and also in the Torat Ḥattat (Kracow, n.d.) and Darkhei Moshe of Moses *Isserles (extracts were published as glosses to the Sha'arei Dura (Venice ed., 1548) of Isaac of Dueren). Some piyyutim and prayers are also attributed to him. Some of Isserlein's responsa found their way into the collections of responsa by Jacob *Weil and of his pupil Israel *Bruna. Isserlein's works contain valuable material on the general history of the Jews of Germany in the 15th century and in particular on the organization of the communities and their spiritual life.
Berliner, in: MGWJ, 18 (1869), 130–5, 177–81, 224–33, 269–77, 315–23; Guedemann, Gesch Erz, 3 (1888), 14, 18, 23, 29, 85, 87, 93, and passim; Weiss, Dor, 5 (19044), 248–52; S. Krauss, Die Wiener Geserah vom Jahre 1421 (1920), index S.V.; Tamar, in: Sinai, 32 (1953), 175–85; S. Eidelberg, Jewish Life in Austria (1962). ADD. BIBLIOGRAPHY: