1914 Albert Einstein returns to Germany to occupy the most prestigious and best-paying post a theoretical physicist can hold in central Europe: professor at the Kaiser-Wilhelm Gesellschaft in Berlin, but does not reapply for German citizenship. He is one of only a handful of German professors who remained a pacifist and did not support Germany's war effort. Although he held a cross-appointment at the University of Berlin, from this time on, he will never again teach regular university courses, but remains on the staff until 1933.