Hans Freudenthal (* September 17th 1905 in Luckenwalde, † October 1990 in Utrecht)
Being out of Germany had the advantage to Freudenthal that, when the Nazis came to power in 1933 and passed legislation to deprive Jews of their jobs, he could continue with his teaching and research in Amsterdam. He wrote important papers on a spectral theorem for Riesz spaces in 1936 and on the suspension theorems in 1937. He was working on the algebraic characterisation of the topology of the real semisimple Lie groups in 1940 when Germany invaded The Netherlands.
Now being of Jewish background became highly significant. The Nazi invaders now did not allow Freudenthal to continue to undertake his duties at the University.
Indeed the circumstances were difficult and during this period of German occupation of that city, 70,000 Jewish inhabitants were deported, many going to their deaths in the concentration camps. Freudenthal and his family had to remain in hiding.
In May 1945 Amsterdam was liberated by Canadian troops and soon after this Freudenthal was able to resume his duties at the university. He was offered the chair of pure and applied mathematics and foundations of mathematics at Utrecht University and he took up his duties there in 1946. He would hold this chair until he retired in 1975.