German Mathematical Society
Following World War II, he was reappointed as a professor at the University of Tübingen, and was instrumental in the organisation of a mathematical congress in Tübingen in autumn 1946, the first scientific congress in Germany after the war. In 1948, he re-established the German Mathematical Society, and was the chairman until 1952, when he became vice-president of the International Mathematical Union, which he remained until 1954.