Rabbi Yaakov Baal HaTurim
After Mishne Torah, the next major halachic code was Rav Yaakov the son of Asher's Rosh Arba'ah Turim (lit. "four pillars"). He dealt only with the laws that are still relevant, and divided them into four major sections: Orach Chayim, dealing with the daily laws and laws of Shabbat and holidays, Yoreh De'ah, dealing with laws of kashrut, mourning, and niddah, Even HaEzer, dealing with women's issues such as marriage and divorce, and Choshen Mishpat, which deals with the civil code. These divisions became the standards for many later works, and this work remains as the standard source-text for halachic discussions. In addition, he also wrote a brief commentary on the Torah, known as Ba'al HaTurim, which focuses on gematria, as well as a longer commentary. He studied under his father, and was the teacher of Abudraham.