Isaac Newton proposed the three laws of motion and universal gravitation in his Principia.
Newton published Philosophiæ Naturalis Principia Mathematica in 1687. The work presented mathematical laws describing motion and a law of universal gravitation, which states that every mass attracts every other mass. Together, these ideas provided a powerful framework for explaining falling objects, planetary orbits and tides.
Newton built on earlier work by scientists including Galileo Galilei and Johannes Kepler. Kepler had described planetary motion, while Newton showed how such patterns could follow from a general gravitational law. This connection between terrestrial and celestial motion was one of the book’s major achievements.
Newton’s mechanics remained central to physics for centuries, although Einstein’s theories later showed that Newtonian laws are an approximation in extreme conditions, such as very high speeds or intense gravity. The famous apple story is a popular anecdote, not a complete account of how Newton developed his theories.