Leonardo da Vinci designed the viola organista, a keyboard instrument with rotating bowed strings.
The concept appears in Leonardo’s notebooks, including the Codex Atlanticus, and is generally associated with the late fifteenth century. Pressing keys would have selected strings while a rotating wheel or belt continuously rubbed them, producing sound in a way related to bowed string instruments.
Leonardo explored several versions rather than leaving one fully standardized instrument. The design combined the keyboard’s ability to play chords with the sustained tone of a bow. It was never widely adopted in Renaissance musical practice, and no original Leonardo instrument is known to survive.
The viola organista is often confused with a conventional organ because of its name, but it does not primarily make sound with organ pipes. It is also different from the hurdy-gurdy, whose wheel bows strings but whose strings are normally controlled by a keyboard or keys in a different arrangement.