Conversation so far:
Who were notable Royal Philharmonic Orchestra members?
Among the well-known musicians who have been Royal Philharmonic Orchestra principals include Steven Staryk, Raymond Cohen, Alan Loveday, Erich Gruenberg, Barry Griffiths, Jonathan Carney and Frederick Riddle.

Question: When were they made notable, what year?
Self-contained rewrite: When were some Royal Philharmonic Orchestra members promoted to principal and in what year?