Mann responds to his correspondent's request: "I sincerely regret to be unable to answer your inquiry. When leaving Germany, I lost the greater part of my library and am no longer in the possession of Bergson's works. Therefore, I cannot look up the quoted passage." When Adolf Hitler came to power in 1933, Mann fled to Switzerland, and when war broke out in 1939, he moved to the United States. The Manns were prominent members of the German expatriate community in California, and Mann became a naturalized United States citizen on 23 June 1944.