Simplify the following text for a Grade 8 native English-speaking person.
Original: In the summer of 1858 , Grieg met the eminent Norwegian violinist Ole Bull , who was a family friend ; Bull 's brother was married to Grieg 's aunt .
Simplified: In the summer of 1858 Grieg met the great Norwegian violinist Ole Bull , who was a friend of the family , and whose brother was married to Grieg 's aunt .