Joseph-Louis Lagrange
1736-1813

Born in Turin in a French family with Italian connections. Appointed Professor of Mathematics at the Royal Artillery School in Turin in 1753 (age 17). Succeeded Euler as the Professor of Mathematics in Berlin, 1766. Moved to Paris, École Normale Superieur, 1787, École Polytechnique, 1795. Was chiefly responsible for the establishment of the metric system.

Developed generalized coordinates, Lagrange's equations of motion, 1760. Extended the principle of least action to the general case in 1760, following earlier work by Euler, Maupertuis (1744). Solved the isoperimetric problem and formulated the calculus of variations, 1761. Sent solution to Euler, who had also solved the problem differently but had not published the result and gave Lagrange credit. Introduced the potential function and the Lagrangian L = T - V, 1773. Developed the analytic approach to dynamics (as contrasted with the more geometric approach followed by Newton's successors). Results summarized in the classic treatise Mécanique Analytique, 1788. Regarded as one of the major mathematicians of the late 18th and early 19th century.