Simplify the following text for a Grade 7 native English-speaking person.
Original: Max Rostal ( born Cieszyn , 7 August 1905 ; died Bern , 6 August 1991 ) was a violinist who was a famous violin teacher .
Simplified: Max Rostal ( 7 July 1905-6 August 1991 ) was a violinist and a viola player .