Every branch of mathematics was enriched by the contributions of the Italian-born French mathematician Comte Joseph Louis Lagrange (1736-1813). He is best known for his analytical formulations of the calculus of variations and mechanics.

Joseph Louis Lagrange was born in Turin on Jan. 25, 1736; both his parents had French ancestors, and Lagrange wrote all his works in French. At the College of Turin he studied classics until, at the age of 17, his interest in mathematics was aroused by reading Edmund Halley's memoir on the utility of analytical methods in the solution of optical problems. Within 2 years Lagrange had made sufficient progress to be appointed professor of mathematics at the artillery school in Turin.

After reading Leonhard Euler's work on isoperimetric problems Lagrange developed an analytical method of solution in 1756. Two years later he helped to found a society which later became the Turin Academy of Sciences. He contributed many...