Leonardo da Vinci invented the viola organista, a stringed keyboard instrument played with continuously bowed strings.
Leonardo’s surviving drawings show a keyboard controlling a set of strings while rotating wheels or a bowing mechanism rub against them. Pressing keys selected the pitches, combining the layout of a keyboard with the sound-producing principle of bowed string instruments.
The instrument was not a conventional piano. A piano strikes strings with hammers, whereas the viola organista was designed to sustain sound through friction from rotating surfaces. It also differed from a harpsichord, whose strings are plucked.
Leonardo drew several versions, but no original Renaissance instrument is known to survive. Modern builders have constructed replicas from his plans, allowing researchers and musicians to explore how the unusual mechanism may have sounded.