Simplify the following text for a Grade 9 native English-speaking person.
Original: He wrote one concerto each for flute , oboe ( later rearranged for flute and known as Flute Concerto No. 2 ) , clarinet , and bassoon , four for horn , a Concerto for Flute , Harp , and Orchestra , and a Sinfonia Concertante for Violin , Viola and Orchestra .
Simplified: He also wrote concertos for more than one soloist e.g. a flute and harp concerto and a violin and viola concerto which he called Sinfonia Concertante .