Rabbi Yosef Karo's Shulchan Aruch and the Rema's Mappah

Rabbi Yosef Karo was born in Toledo in 1488 and carried out of Spain at four. He lived a wanderer's life—Portugal, Turkey, Salonika, Adrianople—and settled in Safed. For twenty years he wrote the Beit Yosef, an immense survey of the whole halakhic tradition arranged on the Arba'ah Turim of Rabbi Yaakov ben Asher, deciding disputes by the majority among three pillars: Rif, Rambam and Rosh.

Then he did the decisive thing: he compressed that ocean into a short practical book with no argument and no proof, only the ruling. The Shulchan Aruch, 'the Set Table', appeared in Venice in 1565 in four parts—Orach Chaim (prayer, Shabbat, festivals), Yoreh De'ah (kashrut, mourning, ritual law), Even ha-Ezer (marriage and divorce), Choshen Mishpat (property and courts). His preface says it suits even a busy man: read it and know what to do.

Ashkenazim did not accept it at once, since it rested on Sephardic rulings and ignored German and Polish custom. The answer came from Rabbi Moshe Isserles of Krakow, the Rema, who wrote not a rival code but brief insertions—the Mappah, 'the tablecloth for the set table'—noting where 'our custom differs'. In 1578 a Krakow edition printed both texts together, and they have been inseparable since.