Leonardo da Vinci designed the viola organista by combining features of a viola and a keyboard. The instrument used keyboard keys to control strings rubbed by rotating wheels, producing a sustained bowed-string sound.
Leonardo drew several versions of the concept in his notebooks. A player would press keys much as on a keyboard, while the mechanism brought strings into contact with a continuously moving wheel. This arrangement aimed to give a keyboard player the expressive quality associated with bowed instruments.
The viola organista is not the same as a pipe organ, harpsichord, or ordinary viola. Its name reflects the hybrid idea: “viola” refers to the bowed-string sound, while “organista” points to keyboard operation. The device was technically ambitious because it required precise alignment, friction control, and dependable motion.
Leonardo did not leave evidence of a completed working instrument. Modern builders have reconstructed versions from his drawings, helping demonstrate how the mechanism may have sounded and operated.