During the Classical period, many changes were occurring across Europe and America, including the French Revolution, Industrialization, and the rise of slavery. Music began to reflect these societal changes. Chamber music was often performed in the homes of the upper classes and used string instruments, woodwinds, and piano or harpsichord. Operas were commonly written and performed in Italian and German, while sonatas like Beethoven's Moonlight Sonata became popular forms of classical music. Spirituals also emerged as a musical style for the common people.