It was regarded as the world's preeminent university for the natural sciences during the 19th and early 20th century, as the university is linked to major breakthroughs in physics and other sciences by its professors, such as Albert Einstein. Past and present faculty and notable alumni include 57 Nobel Prize laureates (the most of any German university by a substantial margin), as well as eminent philosophers, sociologists, artists, lawyers, politicians, mathematicians, scientists, and Heads of State; among them are Albert Einstein, Karl Marx, Friedrich Engels, Otto von Bismarck, W. E. B. Du Bois, Angela Davis, Arthur Schopenhauer, Georg Wilhelm Friedrich Hegel, Walter Benjamin, Max Weber, Georg Simmel, Karl Liebknecht, Ernst Cassirer, Heinrich Heine, Max Planck and the Brothers Grimm.