Isaac Newton was an English mathematician, natural philosopher, theologian, alchemist and one of the most influential scientists in human history. His Philosophiae Naturalis Principia Mathematica is considered to be one of the most influential books in the history of science, laying the groundwork for most of classical mechanics by describing universal gravitation and the three laws of motion. In mathematics, Newton shares the credit with Gottfried Leibniz for the development of the differential and integral calculus. Because of the resounding impact of his work, Newton became a science icon, as did Albert Einstein after publishing his theory of relativity more than 200 years later. Many books, plays, and films focus on Newton or use Newton as a literary device. Newton's stature among scientists remains at the very top rank, as demonstrated by a 2005 survey of scientists in Britain's Royal Society (formerly headed by Newton) asking who had the greater effect on the history of science, Newton or Albert Einstein. Newton was deemed the more influential. In 1999, leading physicists voted Albert Einstein "greatest physicist ever"; Newton was the runner-up.