He was rector of the Technical University of Munich from 1954 to 1956 and president of the Bavarian Academy of Sciences and Humanities from 1964 to 1970.
[1] After graduating from high school in Bamberg and completing his military service in World War I as a non-commissioned officer in the artillery, Sauer studied mathematics and physics at the Technical University of Munich from 1919.
During this time, Sauer joined the Nazi Party and became involved in the National Socialist German Lecturers League.
During World War II he worked on ballistics and supersonic gas dynamics, constructing analog computers to solve the differential equations involved.
In 1948, he became a professor at the Technical University of Munich and director of the Mathematical Institute - especially at the instigation of his friend Josef Lense.