Bernhard Riemann(1826-1866): Riemann showed an interest in mathematics form an early age but when he first entered university it was in the faculty of theology, to please his father. However, soon after, with permission from his father, he switched to mathematics at the University of Gottingen where Gauss was head of mathematics. A year later Riemann left and went to school in Berlin, for Gauss was unapproachable, especially to lowly first year students, and in Berlin he was accepted with open arms by Dirichlet. A few years later Riemann returned to Gottingen and impressed Gauss with a very famous lecture on geometry. He would eventually become a professor at the university. Riemann's definition of an integral is still used in virtually all text books today. Riemann died at the young age of 39 from tuberculosis and for this reason published a relatively small (yet important) amount of work. He left mathematicians to follow the Riemann Hypothesis, which has yet to be solved.