JACOB BEN ASHER (1280–1340), codifier of Jewish law, was born in Germany and died in Toledo. A son of Asher ben Yeḥiel (q.v.), Jacob helped to re-introduce the older elaborate method of legal casuistry which had been overthrown by Maimonides (q.v.). The Asheri family suffered great privations but remained faithful in their devotion to the Talmud. Jacob ben Asher is known as the Ba‘al ha-ṭurim (literally “Master of the Rows”) from his chief work, the four Ṭurim or Rows (the title is derived from the four Ṭurim or rows of jewels in the High Priest’s breastplate). In this work Jacob ben Asher codified Rabbinic law on ethics and ritual, and it remained a standard work of reference until it was edited with a commentary by Joseph Qaro, who afterwards simplified the code into the more popular Shulḥan Aruch. Jacob also wrote two commentaries on the Pentateuch.
See Graetz, History of the Jews (Eng. trans.), vol. iv. ch. iii.; Weiss, Dor dor we-dorashav, v. 118–123. (I. A.)