Isaac ben Abba Mari

Isaac ben Abba Mari (c. 1122 – c. 1193), often simply referred to as "Ba'al ha-Ittur," was a Provençal rabbi and author of Ittur Soferim that hailed from Marseilles. His opus magnum, Ittur Soferim, treats on the Jewish conjugal laws between a man and his wife, as also a treatise on monetary laws, and another on the Jewish holidays, as also a portion of the laws governing kashrut. He largely basis his own work on the juridical decisions passed down by the Babylonian geonic authority.