Russell’s rejection in 1898 of the doctrine of internal relations — the view that all relations are grounded in the intrinsic properties of the terms related — was a decisive part of his break with Hegelianism and opened the way for his turn to analytic philosophy. Before rejecting it, Russell had given the doctrine little thought, though it played an essential role in the most intractable of the problems facing his attempt to construct a Hegelian dialectic of the sciences. I argue that it was Russell’s early reading of Leibniz, in preparation for his lectures on Leibniz given at Cambridge in 1899, that most probably alerted him to the role the doctrine was playing in his own philosophy. Leibniz defended a similar doctrine and extricated it from difficulties like those faced by Russell by means of devices that were not open to Russell. Russell would have come across these views of Leibniz in writings by Leibniz that he read in the summer of 1898, just before he rejected the doctrine of internal relations.ReferencesF. H. Bradley. Appearance and Reality. Oxford: Clarendon Press, 1968. Originally published 1893.Nicholas Griffin. Russell’s Idealist Apprenticeship. Oxford: Clarendon Press, 1991.Nicholas Griffin. Russell and Leibniz on the Classification of Propositions. In Ralf Krömer and Yannick Chin-Drian, editors, New Essays on Leibniz Reception. Basel, Birkhäuser, pp. 85–127, 2012.http://dx.doi.org/10.1007/978-3-0346-0504-5G. W. Leibniz. Die Philosophischen Schriften von Leibniz, 7 Volumes. Edited by C.I. Gerhardt. Berlin, Weidman, 1875–90.G. W. Leibniz. The Philosophical Works of Leibnitz. Edited by G.M. Duncan. New Haven, Tuttle, Morehouse and Taylor, 1890.G. W. Leibniz. New Essays Concerning Human Understanding, Translated by A.G. Langley. London, Macmillan, 1896.G. W. Leibniz. The Monadology and other Philosophical Writings. Edited by R. Latta. Oxford: Oxford University Press, 1898.G. W. Leibniz. Philosophical Papers and Letters, 2 Volumes. Edited by L.E. Loemker. Chicago, University of Chicago Press, 1956.G. W. Leibniz. New Essays Concerning Human Understanding, Translated and Edited by Peter Remnant and Jonathan Bennett. Cambridge, Cambridge University Press, 1981.Massimo Mugnai. Leibniz’ Theory of Relations. Stuttgart: Steiner, 1992.Massimo Mugnai. Leibniz’s Ontology of Relations: A Last Word?. In Oxford Studies in Early Modern Philosophy, Volume IV. Edited by Daniel Garber and Donald Rutherford. Oxford, Oxford University Press, 2012.http://dx.doi.org/10.1093/acprof:oso/9780199659593.001.0001Walter H. O’Briant. Russell on Leibniz. Studia Leibniziana, 11: 159–222, 1979.B. Russell. An Essay on the Foundations of Geometry. New York, Dover, 1956.B. Russell. My Philosophical Development. London, Allen and Unwin, 1959.B. Russell. The Principles of Mathematics. London: Allen and Unwin, 1964.B. Russell. The Monistic Theory of Truth. In Philosophical Essays New York, Simon and Schuster, pages 131–46, 1968.B. Russell. A Critical Exposition of the Philosophy of Leibniz. London, Allen and Unwin, 1975.B. Russell, The Collected Papers of Bertrand Russell, vol. 1, Cambridge Essays, 1888–99, edited by Kenneth Blackwell, et al. London, Allen and Unwin, 1983.B. Russell. The Collected Papers of Bertrand Russell, vol. 2, Philosophical Papers, 1896–99, edited by Nicholas Grif?n and Albert C. Lewis. London, Routledge, 1989a.B. Russell. On the Relations of Number and Quantity (1897). In Russell [1989a], pages 70–82, 1989b.B. Russell. An Analysis of Mathematical Reasoning (1898). In Russell [1989a], pages 163–241, 1989c.B. Russell. The Classification of Relations (1899), in Russell [1989a], pages 138–46, 1989d.B. Russell. The Fundamental Ideas and Axioms of Mathematics (1899). In Russell [1989a], pages 265–305, 1989e.B. Russell. The Collected Papers of Bertrand Russell, vol. 3, Towards “The Principles of Mathematics”, 1900–02, edited by Gregory H. Moore. London, Routledge, 1993a.B. Russell. The Principles of Mathematics, 1899–1900 Draft. In Russell [1993a], pages 13–180, 1993b.B. Russell. The Collected Papers of Bertrand Russell, vol. 11, Last Philosophical Testament, 1943–68. Edited by John G. Slater. London, Routledge, 1997.