Leonardo da Vinci’s viola organista is a mechanical instrument that combines a keyboard with bowed strings.
Leonardo designed several versions of the instrument in the late fifteenth and early sixteenth centuries. Pressing a key was intended to activate a mechanism that brought rotating wheels, or a continuous bowing surface, into contact with strings. This allowed the player to control pitch from a keyboard while producing a sustained bowed-string sound.
The viola organista was never completed by Leonardo, and surviving drawings show more than one arrangement. It is therefore not a single fully standardized instrument in the way that a modern piano is. The name is a later description of the concept, linking the sound of violas with the keyboard action of an organ.
Modern builders have reconstructed versions from Leonardo’s sketches. These reconstructions demonstrate the ingenuity of the mechanism, but they should not be confused with an instrument that Leonardo successfully manufactured or performed on during his lifetime.