small group who were reasonably knowledgeable about the sciences of the day, and their main theme was to promote educational reform (they were anti-Aristotelian). These pamphlets also promoted an occult view of science containing elements of Paracelsian philosophy, neo-Platonism, Christian Cabala and Hermeticism. In effect, they sought to establish a new form of scientific religion with some pre-Christian elements. Mersenne led the fight against acceptance of these ideas, particularly those of Rosicrucian promoter Robert Fludd, who had a lifelong battle of words with Johannes Kepler. The Rosicrucian ideas were defended by many prominent men of learning, and some members of the European scholarly community boosted their own prestige by claiming to be among the selected members of the Brotherhood. However, it is now generally agreed among historians that there is no evidence that an order of Rosicrucians existed at the time, with later Rosicrucian Orders drawing on the name, with no relation to the writers of the Rosicrucian Manifestoes. During the mid-1630s Mersenne gave up the search for physical causes in the Aristotelian sense (rejecting the idea of “essences”, which were still favoured by the scholastic philosophers) and taught that true physics could be only a descriptive science of motions (Mécanisme), which was the direction set by Galileo Galilei. Mersenne had been a regular correspondent with Galileo and had extended the work on vibrating strings originally developed by his father, Vincenzo Galilei. Music An air attributed to Mersenne was used by Ottorino Respighi in his second suite of Ancient Airs and Dances List of works Euclidis elementorum libri, etc. (Paris, 1626) Les Mécaniques de Galilée (Paris, 1634) Questions inouies ou récréation des savants (1634) Questions théologiques, physiques, etc. (1634) Harmonie universelle First edition online from Gallica (Paris, 1636). Translation to English by Roger E. Chapman (The Hague, 1957) Nouvelles découvertes de Galilée (1639) Cogitata physico-mathematica (1644) Universae geometriae synopsis (1644) See also Cassegrain reflector Catalan–Mersenne number/Catalan's Mersenne conjecture Cycloid Equal temperament Euler's factorization method List of Roman Catholic scientist-clerics Renaissance skepticism Seconds pendulum References Explanatory notes Citations General and cited sources Further reading Baillet, Adrien (1691). Vie de Descartes. Dear, Peter Robert (1988). Mersenne and the Learning of the Schools Ithaca: Cornell University Press. Gehring, F. (1922) “Mersennus, Marin (le Père Mersenne)”. Grove's Dictionary of Music and Musicians (ed. J. A. Fuller Maitland). Grosslight, Justin (2013). "Small Skills, Big Networks: Marin Mersenne as Mathematical Intelligencer". History of Science 51:337–374. Moreau,