A project to study changes in Western musical style from 1300 to 1900, using the digitized collections of several large music repositories. The team notes that in order to understand style change in Western polyphonic music we need to be able to describe acceptable vertical sonorities (chords) and melodic motions in each period, and how they change over time. The project aims to do this for European polyphony from 1300 to 1900, using advanced music information retrieval techniques to study highly contrasting kinds of music that are nevertheless unified by common concepts of tonality, consonance vs. dissonance, and voice leading.