Albert Einstein acquired Swiss citizenship in 1901, which he kept for the rest of his life. In 1905, he was awarded a PhD by the University of Zurich. The same year, he published four groundbreaking papers during his renowned "annus mirabilis" (miracle year) which brought him to the notice of the academic world at the age of 26. Einstein taught theoretical physics at Zurich between 1912 and 1914 before he left for Berlin, where he was elected to the Prussian Academy of Sciences. In 1933, while Einstein was visiting the United States, Adolf Hitler came to power. Because of his Jewish background,
Albert Einstein theoretical physics or mathematics. He strongly advocated the idea of a democratic global government that would check the power of nation-states in the framework of a world federation. The FBI created a secret dossier on Einstein in 1932, and by the time of his death his FBI file was 1,427 pages long. Einstein was deeply impressed by Mahatma Gandhi. He exchanged written letters with Gandhi, and called him "a role model for the generations to come" in a letter writing about him. Einstein spoke of his spiritual outlook in a wide array of original writings and interviews. Einstein stated that