Simplify the following text for a Grade 13 native English-speaking person.
Original: As a composer , he produced a wide-ranging oeuvre of 65 opus numbers , and also taught two generations of well-known organists such as Jehan Alain and Marie-Claire Alain , Jean-Marie Beaudet , Pierre Cochereau , Jeanne Demessieux , Rolande Falcinelli , Jean Guillou , Jean Langlais , Carl Weinrich and Olivier Messiaen , to name only a few .
Simplified: He taught two generations of well-known organists including Jehan Alain , Marie-Claire Alain , Pierre Cochereau , Jeanne Demessieux , Jean Guillou , Jean Langlais , and Olivier Messiaen .