Jacob ben Asher

Jacob ben Asher, also known as Ba'al ha-Turim as well as Rabbi Yaakov ben Raash (Rabbeinu Asher), was probably born in the Holy Roman Empire at Cologne about 1269 and probably died at Toledo, then in the Kingdom of Castile, about 1343.

Jacob was an influential Medieval rabbinic authority. He is often referred to as the Baal ha-Turim' ("Master of the Rows"), after his main work in halakha (Jewish law), the Arba'ah Turim ("Four Rows"). The work was divided into 4 sections, each called a "tur," alluding to the rows of jewels on the High Priest's breastplate. He was the third son of the Rabbi Asher ben Jehiel (known as the "Rosh"), a Rabbi of the Holy Roman Empire who moved to Castile. Besides his father, who was his principal teacher, Jacob quotes very often in the Turim his elder brother Jehiel; once his brother Judah (see Tur Orach Chaim, § 417), and once his uncle Rabbi Chaim (ib. § 49). According to many, Jacob moved to Castile with his father and was not born there.