What type of machine was Leonardo da Vinci’s viola organista designed to be?

Leonardo da Vinci’s viola organista was designed to be a keyboard instrument.

The player would press keys, while an internal mechanism transferred those actions to strings. Leonardo’s concept used rotating friction elements to bow the strings, producing sound in a way unlike the plucking mechanism of a harpsichord. The keyboard therefore controlled the pitch selection even though the sound came from vibrating strings.

Its classification can cause confusion because the instrument also resembles a viola or other bowed string instrument. The decisive feature for this question is how it is played: the performer uses a keyboard rather than holding the instrument against the body and moving a bow by hand.

Leonardo drew several versions and related mechanical ideas. Later builders made playable reconstructions, but the instrument never became a standard part of European musical practice. It remains one of his clearest examples of applying mechanical engineering to music.