Henri Poincaré

French mathematician, physicist and philosopher of science often called the last universalist, the last mathematician to work across essentially the whole of the subject as it stood in his lifetime. He founded algebraic topology with his 1895 paper Analysis situs, won King Oscar II of Sweden's prize competition in 1887 for a memoir on the three body problem whose errors led him to the first description of chaotic dynamical behavior, and is credited alongside Albert Einstein and Hendrik Lorentz as an independent co-discoverer of results underlying special relativity. In 1904 he conjectured, almost as an aside at the end of a sixty five page paper, that every simply connected closed three dimensional manifold is topologically a three sphere, a problem that stood open for nearly a century until Grigori Perelman proved it in 2002 and 2003.