Albert Einstein was a theoretical physicist who developed the theory of relativity, one of the two pillars of modern physics. His work is also known for influencing the philosophy of science. Einstein was born in 1879 in Ulm, in the Kingdom of Württemberg in the German Empire. After immigrating to the United States in 1933, he took a position at the Institute for Advanced Study in Princeton, New Jersey, where he remained until his retirement in 1945. Einstein received the 1921 Nobel Prize in Physics for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect.