Mario Keßler (born 4 May 1955) is a German historian.He was born in what was then the Soviet sponsored German Democratic Republic (East Germany): he was 34, and working on his habilitation (senior level university qualification) by the time the wall was breached.
German reunification, in 1990, transformed the historiographical context on both sides of the former inner German border, but the changes were particularly stark for scholars who had learned their craft in the east.
By the mid-1990s only around 40 East German professional historians were still in their old posts and by 2017 it was possible to assert that only around ten East German trained historians were employed by universities or reputable apolitical research institutions.
Mario Keßler was one historian who made the professional transition to the post-reunification world successfully.