Very few people knew of the piano until after the Seven Years' War when a young man named Johannes Zumpe fled Germany for London. While there he refined Cristofori's piano, introducing separate sections of black keys as well as treble and bass capabilities. This new piano was extremely difficult to play, and very few people learned how to play the instrument because of this. That changed when Zumpe convinced Johann Christian Bach, the personal music master to Queen Charlotte and an international celebrity, to purchase and play on a Zumpe piano for the first ever Zumpe piano concert in 1768. Because of Bach's fame, the piano soon replaced the harpsichord as the predominant instrument of the time, and later composers such as Mozart and Beethoven chose to play on a Zumpe piano. Bach's fame and the interest of Queen Charlotte helped the piano become a symbol of social status. The turn of the 19th century also saw the rise of the middle class in the Western world. This middle class was eager to showcase their social status, and it became the proper Victorian man's goal to shower his wife and daughters with leisure time and leisure activities, as leisure was a symbol of social status. Consequently, the piano, which was often used for leisure, stood as a testament to a family's position on the socioeconomic ladder. Over the course of the 19th and 20th centuries, the middle class of Europe and North America increased in both numbers and prosperity. This increase produced a corresponding rise in the domestic importance of the piano, as ever more families became able to afford pianos and piano instruction. The piano also became common in public institutions, such as schools, hotels, and public houses. As elements of the Western middle-class lifestyle gradually spread to other nations, the piano became common in these nations as well, for example in Japan. To understand the rise of the piano among the middle class, it is helpful to remember that before mechanical and electronic reproduction, music was in fact performed on a daily basis by ordinary people. For instance, the working people of every nation generated a body of folk music, which was transmitted orally down through the generations and sung by all. The parents of Joseph Haydn (1732–1809) could not read music, yet Haydn's father (who worked as a wheelwright) taught himself to play the harp, and the