This may be digressing the subject, but I found this sentence odd:
"He is believed to have been an Orthodox Christian, of Slavic appearance"
Just exactly what is the "Slavic appearance"? I've met Bulgarians who looked a lot like Greeks or Turks. Yet Bulgarians are Slavs.
Some Russians, who have Tatar features, look kind of like Asians. But the majority of Russians whom I've ever met look just like other northern Europeans. In fact, I think that you could pick out 5 average Russians in Moscow, put them next to 5 Anglo-Americans in Boise Idaho, and you'd be hard-pressed to pick out who came from which country.
Can Russians really tell if someone looks "Slavic"?