Albert Einstein was a theoretical physicist born in Germany who had developed the theory of relativity, one of the two pillars of modern physics (next to quantum mechanics). His work is also known for his influence on the philosophy of science. He is best known to the general public for his E = mc2 mass-energy equivalence formula, nicknamed "the world's most famous equation". He received the Nobel Prize in Physics of 1921 "for his services in theoretical physics and more particularly for his discovery of the law of the photoelectric effect", a crucial step in the development of quantum theory. At the beginning of his career, Einstein thought that Newtonian mechanics was no longer sufficient to reconcile the laws of classical mechanics with the laws of the electromagnetic field. This led him to develop his theory of relativity during his stint at the Swiss Patent Office in Berne (1902-1909) in Switzerland. However, he realized that the principle of relativity could also be extended to gravitational fields and he published an article on general relativity in 1916 with his theory of gravitation. He continued to deal with the problems of statistical mechanics and quantum theory, which led him to explain the theory of particles and the movement of molecules. He also studied the thermal properties of light that laid the foundation for the photon theory of light. In 1917 he applied the general theory of relativity to model the structure of the universe.