Rene Descartes

Born March 31, 1596 Rene Descartes was a mathematician, philosopher and writer who lived in the Dutch Republic. He is called the Father of Modern Philosophy and most of what Western philosophy is can be a response to Descartes. His Meditation on First Philosophy is a standard text in most university philosophy classes. He designed the Cartesian coordinate system and is credited as the founder of analytical geometry which moves on to infinitesimal calculus.
Descartes set down the foundation of 17th century rationalism that was advocated by Baruch Spinoza. He is known for the philosophical statement Found in part IV of Discourse on the Method. Which states, I think, therefore I am.
He worked for twenty years in the Netherlands and managed to revolutionize mathematics and philosophy. In 1633 after Galileo was condemned by the Roman Catholic Church, Descartes abandoned his plans to publish Treatise on the World. In 1937 he did publish portions of this work in three essays including The Meteors, Dioptrics and Geometry plus Discourses on the Method. His essays lay out four rules of thought that is meant to ensure your knowledge rests on a firm foundation. He continued to publish his mathematical and philosophical works for the rest of his life. In 1641 he published Meditation on First Philosophy written in Latin. In 1644 he worked on Principles of Philosophy. In Principia Philosophiae written in 1647 Descartes praises true philosophy as a means to attain wisdom. He also illustrates a fifth reason to attain wisdom. This work was dedicated to Princess Elisabeth of Bohemia.
Descartes died on February 11, 1650 in Sweden. The cause of death is said to have been pneumonia. His books were placed on the Index of Prohibited Books by the Pope in 1663.