Georg Simmel, born in 1858 in Berlin, is recognized as one of the most important sociologists of the 20th century. He studied history, ethnopsychology, and philosophy in Berlin. His first doctoral thesis, dealing with ethnopsychological studies on the origins of music, was rejected due to formal mistakes and too daring hypotheses. The finally accepted thesis had a title The Nature of Matter According to Kant's Physical Monadology. He had to overcome further obstacles to habilitate in philosophy in 1885 and be named private lecturer at the University of Berlin. Despite his great academic success, he often faced anti-Semitic resentments. Thus for example, his first application for associate professorship was declined by the ministry of education. In 1908, despite recommendations by Max Weber and Eberhard Gothein, he couldn’t become professor of philosophy in Heidelberg owing to a anti-Semitic evaluation of a Berlin historian Dietrich Schäfer, who happened to be active in the Pan-German League. Georg Simmel died in 1918 in Strasbourg.