Kepler's laws of planetary motion
Newton's laws were verified by experiment and observation for over 200 years, and they are excellent approximations at the scales and speeds of everyday life. Newton's laws of motion, together with his law of universal gravitation and the mathematical techniques of calculus, provided for the first time a unified quantitative explanation for a wide range of physical phenomena. For example, in the third volume of the "Principia", Newton showed that his laws of motion, combined with the law of universal gravitation, explained Kepler's laws of planetary motion.