Bernhard Riemann
Riemann studied at the universities of Göttingen and Berlin.  During his student days he was developing ideas that were to become very important to modern mathematical physics.  In 1851 he got his doctorate for a dissertation called Foundations for a General Theory of Functions of a Complex Variable.  This was to become very useful in topology which deals with position and place.  When he became lecturer at Göttingen he had to offer three lectures from which the professors would choose one.  One of the professors was Carl Friedrich Gauss who was one of the greatest mathematicians who ever lived.  Gauss asked him to talk about On the Hypotheses that form the foundations of Geometry.  Gauss himself had worked on this subject.  Riemann was terribly nervous about lecturing on this subject in front of the famous Gauss.  When he gave the lecture, it became one of the most famous events in the history of mathematics.  Gauss did not often give praise to younger mathematicians, but he was very enthusiastic.  Riemann’s ideas made it possible for Einstein to develop his theory of relativity more than half a century later.