  Hermann Weyl was born on 9 November 1885 in the small town of  Elmshorn near Hamburg. In 1904 he entered Göttingen University,  where his teachers included Hilbert, Klein and Minkowski. Weyl was  particularly impressed with Hilbert’s lectures on number theory and  resolved to study everything he had written. Hilbert’s work on  integral equations became the focus of Weyl’s (1908) doctoral  dissertation, written under Hilbert’s direction. In this and in  subsequent papers Weyl made important contributions to the theory of  self-adjoint operators. Virtually all of Weyl’s many publications  during his stay in Göttingen until 1913 dealt with integral  equations and their applications.