The Horn (French Horn) is a unique instrument on many levels. It is used in bands, orchestras, solos and other musical settings. It started as a hunting horn instrument and was used in early music without valves.
Horns (French Horns) used a system of closing the bell with the hand to create some notes not possible on the natural horn.
Many years later the valve horn was invented around the time of Beethoven's 9th Symphony with the 4th player using this special design. All horn playing began to change from this sophistication of the instrument.
To this day this 4th part of the Beethoven 9th is considered one of the most difficult parts in all horn literature for Symphonic music.