Franco of Cologne

Franco of Cologne (fl. mid to late 13th century; also Franco of Paris) was a German music theorist, possibly a composer, one of the most influential theorists of the Late Middle Ages, and was the first to propose an idea which was to transform musical notation permanently: that the duration of any note should be determined by its appearance on the page, and not from context alone. The result was Franconian notation, described most famously in his Ars cantus mensurabilis.