Sir Isaac Newton is famously known for discovering the laws of motion and gravity. His work in the 17th century laid the groundwork for classical mechanics, fundamentally changing the way scientists understood motion and forces. In his seminal work, "Philosophiæ Naturalis Principia Mathematica" (1687), Newton formulated the three laws of motion, which describe the relationship between a body and the forces acting upon it. He also articulated the law of universal gravitation, stating that every mass attracts every other mass in the universe. Newton's groundbreaking insights have had a profound and lasting influence on physics and mathematics, shaping our understanding of the physical world.