Simplify the following text for a Grade 10 native English-speaking person.
Original: Copland 's Symphony for Organ and Orchestra ( 1924 ) brought him into contact with Serge Koussevitzky , a conductor known as a champion of `` new music '' , and another figure who would prove to be influential in Copland 's life , perhaps the second most important after Boulanger . Koussevitzky performed twelve Copland works during his tenure as conductor of the Boston Symphony .
Simplified: The famous conductor of the Boston Symphony Orchestra , Serge Koussevitzky , learned about Copland 's music .