  While stationed at Breda, Descartes met Isaac Beeckman (1588–1637). Notes that Descartes kept related to his correspondence reveal that he and Beeckman had become more than simple acquaintances—their relationship was more one of teacher and student (Descartes being the latter). This relationship would rekindle in Descartes an intense interest in the sciences. In addition to discussions about a wide variety of topics in natural science, a direct result of certain questions posed by Beeckman compelled Descartes to write the Compendium Musicae. Among other things, the Compendium attempted to work out a theory of harmony rooted in the concepts of proportion or ratio, which (along the lines of the ancients) attempted to express the notion of harmony in mathematical terms. It would not be published during Descartes’ lifetime. As for Beeckman, Descartes would later downplay his influence.