One of the oldest of instruments, the horn produces sound when air is forced through blowers lips. Notes are played on a valved horn by opening or closing the valves with a button. The valves change the length of the tube which changes the pitch of the sound.
Though very similar to trumpets, the distinction is based on the fact that most trumpets have straight cylindrical tubes while horns tend to have curved, conical forms.
In the Middle East, fancy horns like this were carved.
Early horns were often made of animal materials--tusks or horns. Many were long, like the Alpine horn which ranges from 5 to 15 feet. Modern horns are easier to transport because they take the length of the tube and bend it into the familiar circles and ovals that we associate with the tuba, sousaphone, cornet and French horn.