Boyar/Bolyar is not a "russian-only" title.
I said that I have no idea of it's origin.
Actually...
Wiki told it is "Goes back to word from the Old Russian language, which is borrowed from the Old Slavonic language, which is later became Church Slavonic language, word of the Danube Bulgarian origin".
Also wiki is a bullshit source, but only I have at least now.
Not Russian but Ruthenian
Yeah, and who is Ruthenian if not Russian?
"The name "Old Russian language" does not mean only continuity with the modern Russian language, and is due primarily to self-designation of the eastern Slavs (the Rus), on behalf of the state-forming ethnic or social group Russes. In terms of scientific publications, used for historical Slavic studies. Ger, Altrussisch, Eng. Old East Slavic, Old Ruthenian, Old Rus (s) ian, fr. le vieux russe, Ukr. davnoruska mova, Belarus. starazhytnaruskaya mova."
As I said, wiki is a bs, because it is just coincidence you know, that there were some Rus or Russes, and it doesn't mean Old Russian language have something with Russians. Lol.