Adrien-Marie Legendre | Biography

Born into a well-to-do family, Adrien-Marie Legendre decided early in life to dedicate himself to the study of mathematics. He enrolled at the College Mazarin in Paris, France, concentrating on science and mathematics. Although independently wealthy, he accepted a position as lecturer in mathematics at the Ecole Militaire in Paris in 1775. He left the post in 1780 to pursue his own research.

In 1782 he won a prize awarded by the Berlin Academy for an essay he wrote concerning ballistics, velocity and missile projections. Based upon that success, his reputation grew, and he attracted the attention of his fellow mathematicians. One year later he was elected to a position in the French Academy of Sciences, replacing French mathematician Pierre Laplace.

In the years following this appointment, he published many papers on a variety of subjects, but focused primarily on three: celestial mechanics, number theory and the theory of elliptic functions. His career at the Academy flourished and he advanced to the position of associate professor in 1785. In 1786 he published Memoires de l'Academie, a study into the branch of calculus dealing with elliptic integrals. This became the basis for Legendre's important work on elliptic functions in 1825 and 1826.

With the outbreak of the French Revolution, all research at the Academy was suppressed. Legendre found his personal fortune gone and was forced to seek employment. In 1794, he became professor of mathematics at the Institut de Marat. He later he worked for the French government in a position concerned with standardizing weights, measures, inventions and the advancement of science. Also in 1794 he published Eléments de géométrie, a highly regarded work which became a standard in the instruction of elementary geometry for the next century.

From 1799 to 1815 he served as a mathematical examiner at the Ecole Polytechnique, publishing Nouvelles méthodes pour la détermination des comètes in 1806. Involving the calculation of planetary orbits, the book is significant as it contains an account of the method of least squares. A bitter dispute developed when German mathematician Carl Friedrich Gauss declared that he had been using the method since 1795, although he had never published his work. As Gauss and Legendre had already battled over another discovery five years earlier, this new assertion only served to deepen the bitterness between them. It has generally been concluded that both men developed the method of least squares independently of each other; history credits Gauss with its earliest discovery and use, Legendre with its first published account.

The years following 1806 were perhaps Legendre's most successful. During this time he produced significant work concerning elliptic functions while chief of the Bureau des Longitudes in Paris, a position he retained until his death in January 1833.