Gilles Personne de Roberval is generally considered to be the founder of kinematic geometry (a branch of mechanics that deals with pure motion) because of his discoveries about plane curves and the method he developed for drawing the tangent to a curve. He was also important historically because of his close contact and correspondence with many of the other important mathematicians of his day. Roberval was a leading expert in the geometry of infinitesimals.

Roberval was born near Senlis, France on August 10, 1602, the son of a poor Catholic farmer. According to historical records, he had no formal schooling until he became intensely interested in mathematics at age 14. At that point, or perhaps before, he left his family and began traveling around the country making a living as a tutor. Roberval took classes at the universities he found himself near, in this manner gaining a more complete education in...