One thing I know is that if you would convert his money to modern time he would have ($253.5 Billion) and be the 3rd richest man after John Rockfeller ($318.3 Billion) and Andrew Carnegie ($298.3...
As far as I know "white Russia" is a literal translation of "Belorussia" (Used to be a part of Russia, now a small independent state). In medieval Russian "white" meant "tax-liberated"... Maybe...