What two technologies did Leonardo da Vinci’s viola organista combine?

Leonardo da Vinci’s viola organista combined a keyboard with bowed strings.

Leonardo designed the viola organista in the late 15th century. The instrument used a keyboard to control strings while a continuously moving wheel or belt rubbed against them, producing sound in a way related to a bowed string instrument. The player could therefore use keyboard-style fingerings while generating sustained string tones.

The design appears in Leonardo’s notebooks and went through several imagined forms. It was never known to have been completed by Leonardo, and no original instrument survives. The concept occupies an unusual place between the organ and the string family because its keys control the sounding mechanism, but its strings are excited by friction rather than struck.

Several modern builders have constructed playable versions. These instruments help demonstrate the mechanical idea, but their sound and construction should not be treated as exact proof of what Leonardo’s finished instrument would have sounded like.