Joseph-Louis Lagrange (1736-1813)
Lagrange was born in Turin, Italy. As a young student he already exhibited his mathematical talent, and his letter to Euler (then in Berlin) showing his method of maxima and minima (calculus of variations) impressed Euler.
In the following ten years, Lagrange published many important results, including the introduction of the Lagrangean function, in Turin. After a few unsuccessful invitations by the Berlin Academy of Science , Lagrange finally accepted a position at Berlin in 1766, as a successor of Euler (who returned to St. Petersburg, Russia). He spent 21 years in Berlin, and his contributions in the field of mechanics culminated in Mechanique Analytique (1788). Thus he became one of the founders of analytical mechanics, a powerful and indispensable tool for modern physics.
In 1787, Lagrange accepted a membership of the Academy of Sciences in Paris. After the French Revolution, Ecole Polytechnique (1794) and Ecole Normale (1795) were founded, and Lagrange began to teach there. He stayed in France until his death.