Peter Gustav Lejeune Dirichlet

Johann Peter Gustav Lejeune Dirichlet (; German: [ləˈʒœn diʁiˈkleː]; 13 February 1805 – 5 May 1859) was a German mathematician. In number theory, he proved special cases of Fermat's Last Theorem and created analytic number theory.

Source: Wikipedia — Peter Gustav Lejeune Dirichlet (CC BY-SA 4.0)