Kievan Rus did not exist for another 800+ years after Jesus died, so I assume that this is about a reincarnation of Jesus. If someone claimed to be the reincarnation of Jesus in the Tsardom of Russia, he would be killed quickly as a threat to the Romanovs and the Orthodox church, which had enough riots on their hands without someone claiming to be their messiah. Also, Jesus secondcomming would bring world peace to proove that he's messiah, which has not happened so far.