This paper assesses the influence of Fatio de Duillier in facilitating the transmission of Newton's public and private ideas to the Netherlands.  When Fatio arrived in London in the spring of 1687 he had benefitted from a number of months studying with Christiaan Huygens, and had just published a work on tangents in the Bibliotecque Universelle.  Inclined to Cartesian-type explanations of physical phenomena, and with every reason to believe he was at the cutting edge of research in mathematics and natural philosophy, he had arrived at an auspicious moment in the history of science.  Alerted to the impending publication of the Principia he informed Huygens that Newton's acolytes had told him that physics had been changed forever by its contents.  Not only was he already in an enviable position within European natural philosophy by the late 1680s, but the Glorious Revolution gave him an even more central role in managing the relations between Huygens and Newton.  He insinuated himself into Newton's inner political circle and was present while Huygens and Newton met each other in the summer of 1689.  

Over the next three years he continued to report the views of each philosopher to the other and travelled between England and the Netherlands on a number of occasions.  In combining the roles of expositor, diplomat and translator, Fatio initially displayed a great deal of balance and subtlety, but at some point he tied his mast to the Newtonian philosophy.  Already in 1691, for example,he was privately asserting to Huygens the priority of Newton over Leibniz in inventing the calculus.  He acted as the official spokesperson for the Newtonian philosophy and assured Huygens of Newton's goodwill in accepting criticisms of his theories of gravity and light, while he translated French works for the Englishman.  Beyond this intermediate role, Fatio forged new opportunities for himself, such as assuming the mantle of 'editor' of a proposed second edition.  If he had had his way it would have had an introductory essay offering a definitive mechanical account of the physical causes of gravity.  Fatio's importance for Huygens had diminished by the time Newton suffered his breakdown in 1693, and he was in any case increasingly involved in watch-making and seeking a position as tutor.