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,
Political views of Albert Einstein to eliminate Einstein's work from the German lexicon as unacceptable "Jewish physics" ("Jüdische Physik"). Instructors who taught his theories were blacklisted, including Nobel laureate Werner Heisenberg, who had debated quantum probability with Bohr and Einstein. Philipp Lenard claimed that the mass–energy equivalence formula needed to be credited to Friedrich Hasenöhrl to make it an Aryan creation. A man convicted of inciting others to kill Einstein was fined a mere six dollars. After World War II ended, and the Nazis were removed from power, Einstein refused to associate with Germany. Einstein refused several honors bestowed upon him by Germany, as he