In 1925 he became full professor at University of Königsberg; he stayed until 1933, when he was regarded politically unsound by the Nazis, and dismissed from his chair.
В 1925 он стал профессором Университета Кёнигсберга, где он пребывал до 1933, когда ему пришлось уехать из-за противостояния нацистам.