**Rene Descartes** born in France, of a noble family, received his first instructions at the Jesuit college of La Flèche, graduating in law in Poitier. He was an active participant in various military campaigns such as that of Maurice, the Prince of Nassau, that of Duke Maximilian I of Bavaria, and that of the French army in the siege of La Rochelle. He was friends with the greatest sages of the time as Faulhaber, Desargues and Mersenne and is considered the "Father of Modern Philosophy".

**AND**In 1637 he wrote his most famous treatise, the "Discourse of the Method," where he expounded his theory that the universe was all made of moving matter and that any phenomenon could be explained by the forces exerted by the contiguous matter. This theory was only surpassed by Newton's mathematical reasoning. His philosophical and scientific ideas were very advanced at the time, but his mathematics retained characteristics of antiquity and created Analytic Geometry in an attempt to go back to the past.

**D**During Descartes's time with the Bavarian army in 1619, he discovered the polyhedron formula that usually bears the name Euler: v + f = a + 2 where v, f and f are respectively the number of vertices, faces, and edges of a simple polyhedron. By 1628 he was already in possession of Cartesian Geometry, which today is confused with Analyticism, although the author's goals were so different that in his "Discourse" he was impartial when discussing the merits of Geometry and Algebra. Its aim was by algebraic processes to free Geometry from the use of so many diagrams that plagued the imagination, and to give meaning to the operations of Algebra, so obscure and confusing to the mind, through geometric interpretations.

**D**escartes was convinced that all mathematical sciences start from the same basic principle and by applying their concepts managed to solve the problem of the three and four straight lines of Pappus. Realizing the efficiency of his methods, he published "The Geometry", which consists of three books, where he gives detailed instructions for solving quadratic equations geometrically by means of parables; deals with important Descartes ovals in optics and teaches how to discover rational roots and find algebraic solution of cubic and quadratic equations. In 1649, invited by Queen Christina of Sweden, he established an Academy of Sciences in Stockholm and, as he was never in good health, could not stand the Scandinavian winter, dying prematurely in 1650.