© Science Museum / Science & Society Picture Library
Bernhard Riemann; Florence. ("To the London Mathematical Society, Heidelberg, 72:4:28, A. Stein"). Seated in chair with ornamental legs, one hand in lap, the other on table. Spectacles. The German mathematician Riemann (1826 -1866) worked out his general theory of complex variables whilst at the University of Berlin. This formed the basis of some of his most important work. At Gottingen his Ph.D. thesis studied the theory of complex variables, especially what we now call Riemann surfaces. In 1857 he was appointed profesor at Gottingen and published his masterpiece 'Theory of abelian functions'.