Whose mathematics invented calculus?

Isaac Newton developed his version of calculus, which he called the method of fluxions, in the mid-1660s, but he did not publish it for many years. The German mathematician Gottfried Wilhelm Leibniz developed his own version independently and published first, in 1684. A bitter dispute followed over who deserved credit, and a 1712 Royal Society report ruled in favour of Newton, though Newton himself secretly wrote much of it. Historians now agree that both men invented calculus independently. The notation we use today, including dx and the integral sign, comes from Leibniz.