Constantin Zuckerman  Constantin Zuckerman (; born 1957) is a French historian and Professor of Byzantine studies at the Ecole Pratique des Hautes Etudes in Paris. Academic rank: professor. Highest degree: doctorate. Job title: The Deputy Director of the Centre for History and Civilization of Byzantium, Collège de France. Zuckerman is the author of numerous articles about the Byzantine Empire, the Goths, the Armenians, the Huns, the Turkic peoples, the Khazars, the Magyars and the early Rus, among other peoples. In "On the Date of the Khazars' Conversion to Judaism and the Chronology of the Kings of the Rus Oleg and Igor," Zuckerman used Khazar documents (the Kievian Letter, Khazar Correspondence, and Schechter Letter) to call into question the traditional dates for early Kievan Rus leaders. In the same article he asserted that the Khazars converted to Judaism in 861, during the visit of Saint Cyril.