Joseph-Louis Lagrange was an influential mathematician and astronomer born in 1736 in Turin, Italy. He made significant contributions to various fields, including calculus, number theory, and mechanics. Lagrange is best known for his work on the Lagrangian mechanics, which reformulated classical mechanics and laid the groundwork for modern physics. Lagrange's most notable achievements include the Lagrange interpolation formula and the Lagrange multiplier method, both of which are essential tools in mathematics. He also played a key role in the development of the calculus of variations and made advancements in the study of celestial mechanics, particularly in understanding the motion of planets and moons.