Jonathan Shepard

Jonathan Shepard is a British historian specialising in early medieval Russia, the Caucasus, and the Byzantine Empire. He is regarded as a leading authority in Byzantine studies and on the Kievan Rus. He specialises in diplomatic and archaeological history of the early Kievan period. Shepard received his doctorate in 1973 from Oxford University and was a lecturer in Russian History at the University of Cambridge. Among other works, he is co-author (with Simon Franklin) of ''The Emergence of Rus, 750–1200'' (1996), and editor of ''The Cambridge History of the Byzantine Empire'' (2008).

Among Shepard's theories is that the breakdown in Byzantine-Khazar relations and the shift in Byzantine foreign policy towards allying with the Pechenegs and the Rus against Khazaria was a result of the Khazar conversion to Judaism. Provided by Wikipedia