His Crimean campaign is mentioned in only one source, the Russian version of the Life of St. Stephen of Sougdaia (Stephen of Surozh in Russian), tentatively dated to the 15th or 16th centuries.
His campaign in Crimea is mentioned in only one source, the Russian version of the Life of St. Stephen of Sougdaia (Stephen of Surozh in Russian), tentatively dated to the 14th or 15th centuries.