He spent extensive periods in Paris, Helsinki, and Moscow in the following years before he became a professor for East European History at the University of Cologne.
In 1998 he moved to the University of Vienna, where in 2006 he initiated the Doctoral Programme Austrian Galicia and its Multicultural Heritage.
[1] Until 2016, he remained the responsible editor for one of the most reputable journals in East European studies, the Jahrbücher für Osteuropäische Geschichte.
After his appointment to the University of Vienna, he increasingly included the former Habsburg areas of today's Ukraine (Galicia) in his research.
In 2017, he noted that the West had erroneously "adopted the Russian perspective, which has had the prerogative of interpretation for two centuries," in matters relating to the nations surrounding Ukraine.