Carl Friedrich Gauss
(April 30, 1777 - February 23, 1855)
Johann Carl Friedrich Gauss was a German mathematician and physical scientist who contributed significantly to many fields, including number theory, statistics, analysis, differential geometry, geodesy, geophysics, electrostatics, astronomy and optics.
(September 17, 1826 - July 20, 1866)
Georg Friedrich Bernhard Riemann was an influential German mathematician who made lasting contributions to analysis, number theory and differential geometry, some of them enabling the later development of general relativity.
(April 25, 1849 - June 22, 1925)
Christian Felix Klein was a German mathematician, known for his work in group theory, complex analysis, non-Euclidean geometry, and on the connections between geometry and group theory. His 1872 Erlangen Program, classifying geometries by their underlying symmetry groups, was a hugely influential synthesis of much of the mathematics of the day.