Gottfried Leibniz, German mathematician and philosopher, c 1700.
© Science Museum / Science & Society Picture Library
Engraving by Le Febure after a painting by L P. Gottfried Leibniz (1646-1716) was a rival of Isaac Newton's (1642-1727) and both mathematicians claimed to have invented calculus. In 1711 the Royal Society formally recognised Newton as the inventor, however doubt about the theory's origin remained. 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 He died without recognition and with almost all his work unpublished.