  A study of around 13,000 musical compositions from the Western classical
tradition is carried out, spanning 33 major composers from the Baroque to the
Romantic, with a focus on the usage of major/minor key signatures. A
2-dimensional chromatic diagram is proposed to succinctly visualize the data.
The diagram is found to be useful not only in distinguishing style and period,
but also in tracking the career development of a particular composer.
