René Descartes, Pierre Gassendi, Evangelista Torricelli, Galileo Galilei, Blaise Pascal, Christiaan Huygens and Pierre de Fermat were among the mathematicians who exchanged letters with Marin Mersenne. This mathematician, mainly known to-day for the Mersenne Numbers, assumed the role of collective correspondent, thus publicizing and disseminating the work of some of the greatest thinkers of his age. In 1635, this group formed the informal, private Académie Parisienne, the precursor to the French Academy of Sciences. Certain topics discussed in that group are still debated now.