Enrico Bombieri
Enrico Bombieri (1940 - ) Italian mathematician, best known for the Bombieri-Vinogradov theorem regarding the measure of error in Dirichlet’s theorem on arithmetic progressions, thought to be one possible direction towards proving the Riemann hypothesis
(so much so that the Clay Mathematics Institute asked Bombieri to write the official description for the Millennium Problems). Bombieri was awarded the Fields medal in 1974.