Education
Leiden University.
Leiden University.
Between 1918 and 1925 he worked as a History professor at Leiden University, where his subject was "The history of the Dutch East Indies and Communications Techniques" (de "geschiedenis van Nederlandsch-Indië en de geschiedenis van de methode der zending"). In 1925 the university promoted him to the Professorship in National History.
Royal Netherlands Academy of Arts and Sciences.