Gottfried Leibniz, German mathematician and philosopher, c 1700.
© Science Museum / Science & Society Picture Library
Engraving. Gottfried Leibniz (1646-1716) was a rival to Isaac Newton (1642-1727) and a dispute as to which of the two men invented calculus was partially resolved in 1711 when the Royal Society formally sided with Newton, but the matter was never fully settled. As a philosopher, Leibniz expounded the theory that the Universe is composed of 'monads', a simple substance that is used to create all other compounds. He died without recognition and with almost all his work unpublished.