Felix Hausdorff, who was so well known to American mathematicianAmerican mathematicians through his topology book of 1914, Grundzüge der Mengenlehre, committed suicide together with his wife when facing the threat of deportation to Nazi Concentration camps in 1942.
Based on Wikipedia,Hausdorff hated Nazi as early as early 1930s and asked the mathematician Richard Courant in 1939 for a research fellowship to be able to emigrate into the USA. Does anyone know how Courant replied to Hausdorff and why Hausdorff wasn't able to move to United State? Was it because Nazi stoppeddeterred him or US didn't give him visa?