Simplify the following text for a Grade 9 native English-speaking person.
Original: In 1837 Felix Mendelssohn conducted a performance of his St. Paul oratorio , played the organ , and played the piano part in the premiere of his second Piano Concerto , specially commissioned by the Festival .
Simplified: In 1837 Felix Mendelssohn conducted a performance of his oratorio St. Paul , played the organ , and played the piano part in the first performance of his Piano Concerto No. 2 which had been especially commissioned by the Festival .