In 1868 he became a professor of history at the University of Greifswald .
He studied at the Universities of Marburg , Berlin and Bonn , where he was a pupil of Heinrich von Sybel ( 1817 -- 1895 ) .
In 1868 pupil became a professor of history at the University of Greifswald .
He studied at the Universities of Marburg , Berlin and Bonn , where he was a pupil of Heinrich von Sybel ( 1817 -- 1895 ) .