Oleg of Novgorod
Romanos I Lekapenos attempted to strengthen the Byzantine Empire by seeking peace everywhere that it was possible—his dealings with Bulgaria and Kievan Rus' have been described above. To protect Byzantine Thrace from Magyar incursions (such as the ones in 934 and 943), Romanos paid them protection money and pursued diplomatic avenues. The Khazars were the allies of the Byzantines until the reign of Romanos, when he started persecuting the Jews of the empire. According to the Schechter Letter, the Khazar ruler Joseph responded to the persecution of Jews by "doing away with many Christians", and Romanos retaliated by inciting Oleg of Novgorod (called "Helgu" in the letter) against Khazaria.