Simplify the following text for a Grade 7 native English-speaking person.
Original: Mengelberg died in 1951 just before the end of his sentence , thus never conducting the orchestra after 1945 .
Simplified: In 1945 , after World War II had ended , Mengelberg was not allowed to conduct the orchestra because he had played to the Nazis . He was banned for six years from conducting them , but he died in 1951 just before the six years came to an end .