Simplify the following text for a Grade 9 native English-speaking person.
Original: After taking over Parlophone when Preuss retired in 1955 , Martin spent his first years with the record label recording classical and Baroque music , original cast recordings of hit plays , and regional music from around the British Isles .
Simplified: Martin became an assistant at Parlophone Records , a small record label . Parlophone mostly recorded classical music and original cast recordings of popular stage shows and plays .