Augustin-Jean Fresnel (1788-1827) was an engineer who lost his job after Napoleon returned from Elba in 1815. He became involved in optics and pioneered in establishing the wave theory of light. When he presented the wave theory, Poisson objected that the theory predicted a bright spot in the center of the shadow of a circular object. When this phenomenon was observed by Arago, objection to the wave theory collapsed.