René Perron Descartes was, in my opinion, an amazing philosopher who accomplished many things during his life time. In 1618 René went to Breda, in Holland, and joined the army of Prince Maurice of Nassau. In November he met Isaac Beeckman, a newly graduated physician and scholar, who was impressed by his mathetical ability and encouraged him to devote himself to questions in mechanics. In that year René composed a short treatise on music, the Compedium Musicae (Summary of Music). The following year, travelling in Germany, he stayed at Neuberg-on-Danube, and after a "marvellous discovery" that filled him with enthusiasm he had two nights of dreams on November 10th and 11th. He considered these dreams to be prophetic and decided to "devote all of my life to cultivating reason and advancing as far as I could the knowledge of the truth". He travelled to Italy from March 1623 to may 1625, and afterwards became known as one of the leading thinkers in France through his friendship with Marin Mersenne, a ploymath Catholic priest (also an alumnus of La Fléche). In 1628 he composed the Regulae ad directionem ingenii (Rules for the Direction of the Mind/Native Intelligence). Around 1630 he became interested in more purely scientific matters, such as rainbows, as well as anatomy, and began work on a long scientific treatise entitled Le Monde (The World).