Simplify the following text for a Grade 14 native English-speaking person.
Original: A turning point for Nijinsky was his meeting Sergei Diaghilev , a celebrated and highly innovative producer of ballet and opera as well as art exhibitions , who concentrated on promoting Russian visual and musical art abroad , particularly in Paris .
Simplified: A turning point for Nijinsky was his meeting Sergei Diaghilev , a celebrated producer of ballet and art exhibitions , who concentrated on promoting Russian visual and musical art abroad .