Sir Isaac Newton under the apple tree th century Newton under the apple tree where according to popular legend a falling apple prompted him to devise his theory of gravity Newtons discoveries were prolific and exerted a huge influence on science and thought His theories of gravity and his three laws of motion were outlined in his greatest work Philosophiae Naturalis Principia Mathematica and he is credited with discovering differential calculus He also formulated theories regarding optics and the nature of light that led to him building the first reflecting telescope Knighted by Queen Anne in Newton is buried in Westminster Abbey London