Benedict de Spinoza was among the most important of the post-Cartesian philosophers who flourished in the second half of the 17th century. He made significant contributions in virtually every area of philosophy, and his writings reveal the influence of such divergent sources as Stoicism, Jewish Rationalism, Machiavelli, Hobbes, Descartes, and a variety of heterodox religious thinkers of his day. For this reason he is difficult to categorize, though he is usually counted, along with Descartes and Leibniz, as one of the three major Rationalists.