ZADOK (Isaac) BAR MAR YISHI

ZADOK (Isaac) BAR MAR YISHI (Ashi) (also known as Mar Zadok), gaon of Sura 816–818. Only a few of Zadok's responsa have been preserved, but most of his decisions, halakhic judgments, and ordinances, for example, the imposition of an oath upon a defendant who denies a claim on land (takkanot shevu'ah al kefirat karka'ot), were handed down by his successors in the gaonate. The geonim speak of Zadok with much reverence, amram , for instance, calling him "our master, who enlightens us." Naḥshon Gaon was his son. -BIBLIOGRAPHY: H. Tykocinski, Takkanot ha-Ge'onim (1959), 58–59; Abramson, Merkazim, 2. (Meir Havazelet)