Girard Desargues

Verified Timeline

Lore & Background

Desargues came from a family devoted to service to the French crown. His father was a royal notary, an investigating commissioner of the Seneschal's court in Lyon (1574), the collector of the tithes on ecclesiastical revenues for the city of Lyon (1583) and for the diocese of Lyon. Girard Desargues worked as an architect from 1645. Prior to that, he had worked as a tutor and may have served as an engineer and technical consultant in the entourage of Richelieu. Yet his involvement in the Siege of La Rochelle, though alleged by Ch. Weiss in Biographie Universelle (1842), has never been testified. As an architect, Desargues planned several private and public buildings in Paris and Lyon. As an engineer, he designed a system for raising water that he installed near Paris. It was based on the use of the epicycloidal wheel, the principle of which was unrecognized at the time. His research on perspective and geometrical projections can be seen as a culmination of centuries of scientific inquiry across the classical epoch in optics that stretched from al-Hasan Ibn al-Haytham (Alhazen) to Johannes Kepler, and going beyond a mere synthesis of these traditions with Renaissance perspective theories and practices. Late in his life, Desargues published a paper with the cryptic title of DALG. The most common theory about what this stands for is Des Argues, Lyonnais, Géometre (proposed by Henri Brocard). He died in Lyon.

Reader's Guide

Girard Desargues is significant as one of the founders of projective geometry. His work was rediscovered and republished in 1864. A collection of his works was published in 1951, and the 1864 compilation remains in print. One notable work, often cited by others in mathematics, is 'Rough draft for an essay on the results of taking plane sections of a cone' (1639). His legacy includes Desargues's theorem, the Desargues graph, and the Desargues configuration, all named after him. The lunar crater Desargues also bears his name. His contributions bridged classical optics and Renaissance perspective, influencing later developments in geometry.

Did You Know?

• Desargues's father was a royal notary and an investigating commissioner of the Seneschal's court in Lyon in 1574.
• As an engineer, Desargues designed a system for raising water near Paris based on the epicycloidal wheel, a principle unrecognized at the time.
• His research on perspective and geometrical projections built on work from al-Hasan Ibn al-Haytham (Alhazen) to Johannes Kepler.
• Late in his life, Desargues published a paper with the cryptic title DALG, most commonly interpreted as Des Argues, Lyonnais, Géometre.
• The lunar crater Desargues is named after him.