Einstein, Albert. Physicist. Born in Germany, 1874, of Jewish parentage. At the age of 16 he went to Switzerland, and became a naturalized citizen. He early displayed a genius for mathematics, and became professor of theoretical physics at the Zurich Polytechnic. Shortly before the First World War Einstein was called to Berlin to succeed Van't Hoff, the great Dutch physicist, at the Kaiser Wilhelm Academy for Research. After the war, he moved to the University of Leyden. In 1905, Einstein propounded his first theory of relativity, dealing with physics in general and with light and gravitation in particular. In 1915 Einstein put forward a more generalized theory, and proposed three important astronomical tests of its correctness. The results of two of these tests have since confirmed his predictions, and have won recognition for his theory.