Yaakov ben Moshe Levi Moelin

Rabbi Yaakov ben Moshe Levi Moelin
Maharil
Grave of Yaakov ben Moshe Levi Moelin in Worms, Germany
Personal details
Born	c. 1365 Mainz
Died	September 14, 1427
Buried	Worms
Parents	Rabbi Moshe Levi Moelin

Yaakov ben Moshe Levi Moelin (Hebrew: יעקב בן משה מולין‎‎) (c. 1365 – September 14, 1427) was a Talmudist and posek (authority on Jewish law) best known for his codification of the customs (minhagim) of the German Jews. He is also known as Maharil - the Hebrew acronym for "Our Teacher, the Rabbi, Yaakov Levi" - as well as Mahari Segal or Mahari Moelin. Maharil's Minhagim was a source of law for Moses Isserles’ component of the Shulkhan Arukh.

Maharil was the son and pupil of Moshe Levi Moelin, Rabbi of Mainz, and a pupil of R. Shalom b. Isaac of Wiener Neustadt. At a young age, Moelin was recognized as a budding scholar. In 1387, he succeeded his father as Rabbi of Mainz. He established a yeshiva in Mainz which attracted many students. One of his most noteworthy students was Jacob Weil. Moelin lived through the mass slaughter of Jews in Austria in 1420 and the Hussite wars in 1421, which brought suffering to the Jews of Bavaria and the Rhine; see History of the Jews in Germany. Maharil played an important role in rebuilding these communities. He died and was buried in Worms.

Moelin composed piyyutim for the synagogue. He was also a notable Hazzan who famously ruled that traditional melodies should not be changed. Some traditional melodies attributed to him were still in use in pre-World War II Mainz. He appears also to have been familiar with the study of astronomy.