Nicolas Fatio de Duillier

The astronomer-mathematician Fatio, originator of a mechanistic theory of gravity, is now known primarily as an associate of others. At 18 he introduced himself to Cassini with an account of Saturn’s rings, subsequently studying under him in Paris. Going to the Netherlands to warn William of Orange of a plot against him, he worked with Huygens, then settling in London became Newton’s very close friend (exciting some latter-day speculation as to its nature, Newton seemingly suffering a breakdown when the relationship ended). He was friendly with Locke and corresponded widely, including with Leibniz, whom he charged with ‘stealing’ Newton’s invention of calculus.