Albert Einstein (1879–1955) was born in Germany and became an American citizen in 1940. A world-famous theoretical physicist, he was awarded the 1921 Nobel Prize for Physics and is renowned for his Theory of Relativity. In addition to his scientific work, Einstein was an influential humanist who spoke widely about politics, ethics, and social causes. After leaving Europe, Einstein taught at Princeton University. His theories were instrumental in shaping the atomic age.