Leonardo da Vinci designed the viola organista, a keyboard instrument combining bowed strings with a keyboard.
Instead of plucking strings like a harpsichord, the proposed instrument used rotating, rosined wheels to rub against strings and produce a sustained sound. Pressing keys selected and stopped the strings, adapting keyboard control to a bowed-string principle.
Leonardo drew several versions during the late 15th and early 16th centuries, but no surviving original instrument is known to have been built by him. Modern makers have constructed working reconstructions from his drawings.
The viola organista is therefore a design attributed to Leonardo, not a standard Renaissance instrument he successfully mass-produced. Its name reflects its viola-like sound source and organ-like keyboard mechanism.