>>17954244
Depends on the field and particular person.
Of the composers Tschaikovsky is the most well known and he was some kind of Polish-Russian mixture. The more important(for development of actual russian classical music style) composers like Mussogorsky or Balakirev were like 3/5 fully Russian, one half-russian(the other half georgian) and one French-Lithuanian(and also a general in the Russian army).
When it comes to writers Tolstoy was Russian, Dostoyevsky 3/4th(the other 4th Polish), I dunno who else is commonly brought up(Bulgakov? Iirc his family can be traced back to Pskov and Voronezh, so most likely Russian, Pushkin famously an octoroon and I don't like niggers so one drop rule applies - not Russian).