René Descartes was born at La Haye in Touraine, in 1596, and died at Stockholm in 1650. Of the studies taught in the Jesuit school at La Flèche, mathematics alone was able to satisfy his craving for clear and certain knowledge. The years 1613-17 he spent in Paris; then he enlisted in the military service of the Netherlands, and, in 1619, in that of Bavaria. While in winter quarters at Neuburg, he vowed a pilgrimage to Loretto if the Virgin would show him a way of escape from his tormenting doubts; and made the saving discovery of the "foundations of a wonderful science." At the end of four years this vow was fulfilled. On his return to Paris (1625), he was besought by his learned friends to give to the world his epoch-making ideas. Though, to escape the distractions of society, he kept his residence secret, as he had done during his first stay in Paris, and frequently changed it, he was still unable to secure the complete privacy and leisure for scientific work which he desired. Therefore he went to Holland in 1629, and spent twenty years of quiet productivity in Amsterdam, Franecker, Utrecht, Leeuwarden, Egmond, Harderwijk, Leyden, the palace of Endegeest, and five other places. His work here was interrupted only by a few journeys, but much disturbed in its later years by annoying controversies with the theologian Gisbert Voëtius of Utrecht, with Regius, a pupil who had deserted him, and with professors from Leyden. His correspondence with his French friends was conducted through Père Mersenne. In 1649 he yielded to pressing invitations from Queen Christina of Sweden and removed to Stockholm. There his weak constitution was not adequate to the severity of the climate, and death overtook him within a few months.