Haydn in the context of "Bacchylides"

A fortepiano [ˌfɔrteˈpjaːno] is an early piano. In principle, the word "fortepiano" can designate any piano dating from the invention of the instrument by Bartolomeo Cristofori in 1700 up to the early 19th century. Most typically, however, it is used to refer to the mid-18th to early-19th century instruments, for which composers of the Classical era, such as Haydn, Mozart, and the younger Beethoven and Schubert, wrote their piano music.

Starting in Beethoven's time, the fortepiano began a period of steady evolution, culminating in the late 19th century with the modern grand. The earlier fortepiano became obsolete and was absent from the musical scene for many decades. In the later 20th century, the fortepiano was revived, following the rise of interest in historically informed performance. Fortepianos are built for that purpose, in specialist workshops.

Franz Anton Mesmer (/ˈmɛzmər/ MEZ-mər; German: [ˈmɛsmɐ]; 23 May 1734 – 5 March 1815) was a German physician with an interest in astronomy. He theorized the existence of a process of natural energy transference occurring between all animate and inanimate objects; this he called "animal magnetism", later referred to as mesmerism. Mesmer's theory attracted a wide following between about 1780 and 1850, and continued to have some influence until the end of the 19th century. In 1843, the Scottish doctor James Braid proposed the term "hypnotism" for a technique derived from animal magnetism; today the word "mesmerism" generally functions as a synonym of "hypnosis". Mesmer also supported the arts, specifically music; he was on friendly terms with Haydn and Mozart.