Simplify the following text for a Grade 9 native English-speaking person.
Original: The old valveless horn was barely capable of playing in B-flat minor ; the only example found in 18th century music is a modulation that occurs in the first minuet of Franz Krommer 's Concertino in D major , Opus 80 .
Simplified: The old valveless horn could not play easily in B-flat minor . In fact , the only example found in 18th century music is a modulation in the first minuet of Franz Krommer 's Concertino in D major , Opus 80 .