Leonardo da Vinci invented the viola organista, a keyboard instrument combining features of a piano and a bowed string instrument.
The player would press keys, but instead of striking strings with hammers, the mechanism would bring rotating, rosined wheels or bows into contact with them. This arrangement aimed to produce a sustained, violin-like sound while retaining the organized fingering of a keyboard.
Leonardo drew several versions of the concept in notebooks, showing repeated attempts to refine the mechanism. The instrument was not simply a piano prototype: the crucial idea was continuous friction against strings, similar to how a violin bow creates sound. The design demonstrates Leonardo’s overlapping interests in music, mechanics, and acoustics.
The viola organista is also called a bowed keyboard instrument. It should not be confused with a hurdy-gurdy, which uses a hand-turned wheel to sound strings but normally uses keys only to shorten them. Modern builders have made playable reconstructions based on Leonardo’s surviving drawings.