"Then he studied at the University of Poitiers. He received a law degree in 1616 and then enlisted in the military school at Breda- (Westfall, 1995). "By 1619, under the influence of the Dutch mathematician and scientist Beeckman, Descartes began his exceptionally abundant mathematical studies of natural phenomena. Also around 1619, Descartes may have begun the unfinished Rules for the Direction of the Mind which was his first major philosophical treatise on the proper method for pursuing either science or rational theology- (Burnham & Fieser, 2001). He resigned his commission in the spring of 1621, and spent the next five years in travel, during most of which time he continued to study pure mathematics with a "circle of mathematicians and physicists gathered around the figure of Father Mersenne- (Burnham & Fieser, 2001). .
In 1628 Descartes met "Cardinal de Berulle; the founder of Oratorians- (Ball, 1995). The Cardinal was so impressed by Descartes that he urged him to spend his life devoted to the examination of truth. By this time Descartes was so tired of traveling and wanted to settle down, so he agreed with the Cardinal and moved to Holland. This was a good decision which he did not seem to regret over the next twenty years. While settling in Holland he devoted all his time to mathematics and philosophy, only later did he explore metaphysics. During his studies he came up with a hypothesis: "science may be compared to a tree; metaphysics is the root, physics is the trunk, and the three chief branches are mechanics, medicine, and morals, these forming the three applications of our knowledge, namely, to the external world, to the human body, and to the conduct of life- (Ball, 1995). During this period he produced the writings upon which his fame rests.
Descartes spent four years writing "Le Monde, which embodies an attempt to give a physical theory of the universe- (Ball, 1995), "it was near completion when news that Galileo was condemned to house arrest reached him.