Leibniz’s relationship with the Royal Society is one of tremendous contrast. His early approaches to Henry Oldenburg followed by his first visit to London in 1673 reflect the efforts of a young scholar seeking to make his mark on the leading scientific institution of his day. These efforts were crowned with his admission to the fellowship in April of that year. The contrast with some forty years later, when a committee of the Royal Society was established under Newton’s presidency to adjudicate on the dispute over the discovery of the calculus, leading to the publication of the Commercium epistolicum in 1712, could scarcely be greater. Leibniz’s relations with the Royal Society have been scrutinized before, notably through A. Rupert Hall, Marie Boas Hall, and Joseph Ehrenfried Hofmann. Since their pioneering studies further material has come to light, justifying that a fresh look be taken at the topic. Through the steady progress of the Akademie-Ausgabe of Leibniz’s letters and papers as well as through ongoing work on critical editions of the letters of John Wallis and John Collins, Oldenburg’s most important advisers on mathematical affairs, a lot more is now known about the ways in which news and ideas were communicated and disseminated, how opinions were formed and decisions taken. The chapter seeks to show the complexity of factors which ultimately led to a complete breakdown in trust between Leibniz, Newton and their respective circles.