Career
During the late 1940s and 1950s in stalinist People"s Republic of Poland he was persecuted by the authorities (he was arrested and interrogated by Urząd Bezpieczeństwa). He was a lecturer at the Adam Mickiewicz University in Poznań, where he would become a professor He retired in 1979. Honorary citizen of the city of Poznań since 2005.
His area of specialty included Polish-German relations, particularly during the World World War World War II