German philosopher and mathematician Baron Gottfried Wilhelm Leibniz (1646–1716) was a contemporary of Isaac Newton. He is considered by some to be a forgotten mathematician, being overshadowed by Newton, but his contributions to mathematics were just as important. In addition to many other contributions, he (independently of Newton) developed infinitesimal calculus and was first to describe it in print. Because his work on calculus was published three years before Isaac Newton’s, Leibniz’s system of notation was universally adopted, including the notation for an integral. In 1684, he published Nova methodus pro maximis et minimis, itemque tangentibus, a work detailing differential calculus and containing the familiar d (or d/dx) notation, along with the rules for calculating the derivatives of powers, products, and quotients.