Yechezkel ben Yehuda HaLevi Landau (8 October 1713 – 29 April 1793) was an influential authority in halakha (Jewish law). He is best known for the work Noda Biyhudah (נודע ביהודה), by which title he is also known. Biography Landau was born in Opatów, Poland, to a family that traced its lineage back to Rashi, and attended yeshiva at Ludmir and Brody. In Brody, he was appointed dayan (rabbinical judge) in 1734. In 1745 Landau became rabbi of Yampol. While in Yampol, he attempted to mediate between Jacob Emden and Jonathan Eybeschütz in a debate—"The Emden-Eybeschütz Controversy"—that "had disrupted Jewish communal life for many years". Emden had accused Eybeschuetz of being a crypto Sabbatean, primarily based on amulets Eybeschuetz had written, which Emden believed contained Sabbatean kabbalah. Landau proposed a compromise, in which all amulets allegedly written by Eybeschuetz would be hidden away, and Eybeschuetz would accept to refrain from producing any amulets in the future. Furthermore, all accusations against Eybeschuetz would stop, and no further polemics would be published. Landau's role in the Emden - Eybeschuetz controversy is described as "tactful" and brought him to the attention of the community of Prague—where, in 1755, he was appointed rabbi. He also established a yeshiva there; Avraham Danzig, author of Chayei Adam, is amongst his best known students. Landau was highly esteemed not only by the community, but also by others; and he stood high in favor in government circles. Thus, in addition to his rabbinical tasks, he was able to intercede with the government on various occasions when anti-Semitic measures had been introduced. Though not opposed to secular knowledge, he objected to "that culture which came from Berlin", in particular Moses Mendelssohn's translation of the Pentateuch. His son, Samuel Landau (1752 – 31 October 1834, Prague), was chief dayyan of Prague. Landau was the champion of Orthodox Rabbinism, and when, at the end of the eighteenth century, the Austrian emperor planned the establishment of Jewish theological seminaries, Landau was one of the rabbis that objected thereto. He had a controversy on this subject with Baruch Jeiteles (Phinehas Hananiah Argosi di Silva), who, under the title of Ha-Oreb, published (Vienna, 1795) Landau's letter to him and his own rejoinder. Landau published his responsa under the title of Shibat Ẓiyyon (Prague, 1827). He edited his father's Ahabat Ẓiyyon and Doresh le-Ẓiyyon (ib. 1827), adding to the former work four homilies of his