by Jews. Many of the leading heads of the Social Democratic Party of Austria and especially the leaders of the Austromarxism were assimilated Jews, for example Victor Adler, Otto Bauer, Gustav Eckstein, Julius Deutsch and also the reformer of the school system in Vienna, Hugo Breitner. Due to the Social Democratic Party being the only party in Austria that accepted Jews as members and also in leading positions, several Jewish parties that were founded after 1918 in Vienna, where about 10% of the population was Jewish, had no chance of gaining bigger parts of the Jewish population. Districts with high Jewish population rates, such as Leopoldstadt, the only districts where Jews formed about half of the population, and the neighbouring districts Alsergrund and Brigittenau, where up to a third of the population was Jewish, had usually higher percentage rates of voters for the Social Democratic Party than classical "worker"-districts. The First Republic of Austria denied citizenship to former Habsburg monarchy Jews during the interwar period. Brain drain from Austria already began with the increase of antisemitism after the collapse of the Habsburg Empire. In University of Vienna, violent attacks by German National and National Socialist students against Jewish and socialist classmates increased since the 1920s, particularly at the Institute of Anatomy under Julius Tandler, or on the occasion of the abolishment of the anti-Semitic Gleispach student regulation 1930. In 1921, there was a significant antisemitic mob parade in Vienna. Antisemites began blaming Jews for the downfall of Austria-Hungary and the Central Powers during World War I, similarly to the German "stab-in-the-back" myth. In May 1923, Vienna hosted the First World Congress of Jewish Women in the presence of President Michael Hainisch, calling in particular for support for the relocation of Jewish refugees in Palestine. Also the cultural contribution of Jews reached its peak. Many famous writers, film and theatre directors (e.g., Max Reinhardt, Fritz Lang, Richard Oswald, Fred Zinnemann and Otto Preminger) actors (e.g., Peter Lorre, Paul Muni) and producers (e.g., Jacob Fleck, Oscar Pilzer, Arnold Pressburger), architects and set designers (e.g., Artur Berger, Harry Horner, Oskar Strnad, Ernst Deutsch-Dryden), comedians (Kabarett artists (e.g., Heinrich Eisenbach, Fritz Grünbaum, Karl Farkas, Georg Kreisler, Hermann Leopoldi, Armin Berg), musicians and composers (e.g., Fritz Kreisler, Hans J. Salter, Erich Wolfgang Korngold, Max Steiner, Kurt Adler) were Jewish Austrians. In 1933, many Austrian Jews, who had worked and lived in Germany for years, returned