 Although our evidence of the mathematics that Descartes studied at La Fleche is sketchy, we are quite certain that Descartes’ entrance into the debates of early modern mathematics began in earnest when he met Isaac Beeckman in Breda, Holland in 1618. Among other things, Beeckman and Descartes explored the fruitfulness of applying mathematics to natural philosophy and discussed issues pertaining to physico-mathematics. It is in this period that Descartes composed his Compendium musicae for Beeckman, a text in which he addresses the application of mathematics to music and also famously discusses the law of free fall. (Compare Koyré 1939, 99–128 and Schuster 2013, Chapter 3.5 on Descartes’ treatment of free fall in this early text. For discussion of Descartes’ pursuit of causal knowledge in his physico-mathematical researches in optics during this period, see Schuster 2013, Chapter 3.6.)