What is an arpeggione?

An arpeggione is a bowed, stringed musical instrument that was invented by Johann Georg Staufer in 1823. It is similar to a violoncello, but smaller and with six strings. The arpeggione was designed to be played with the fingers, rather than a bow, and was tuned in the same way as a guitar. The instrument was popular for a time, but its popularity quickly faded and it fell out of use by the mid-19th century.