At eighteen, Poisson caught Legendre’s attention with a paper on finite differences (he later gave Legendre’s funeral oration, saying he had only wanted to be spoken about in terms of his work). Poisson was a student, and later close friend, of both Laplace and Lagrange, and a member of the influential Société d’Arcueil that Laplace and Berthollet founded. Galois, barely twenty, sent Poisson a paper on equation theory, which Poisson thought unclear. Arago, another société d’Arcueil member, wrote Poisson’s biography, reporting his words that he was good for only two things — doing mathematics, and teaching it.