During the 1960s he was a member of the politburo's "Ideology Commission", widely regarded as one of the most committed and effective propagandists among East Germany's mainstream academic historians.
[2][7] Along with his responsibilities at the institute, between 1962 and 1968 Berthold was editor in chief of "Beiträge zur Geschichte der Arbeiterbewegung", an academic journal focusing on the history of the labour movement, a topic of considerable importance for the national leadership.
The crushing of the Prague Spring movement in August 1968 through an invasion by fraternal tanks from around the Warsaw Pact caused unease at many levels in East Germany, but most people kept their doubts to themselves.
Nevertheless, a number of young people, including some of the adolescent children of East German intellectuals, such as Thomas Brasch, Florian Havemann and his girl-friend, Erika-Dorothea Berthold, expressed their opposition to the Warsaw Pact intervention through a series of street protests in Berlin.
[9] After slightly less than three months in investigatory custody, the young people faced trial between 21 and 28 October 1968 and were condemned to prison terms or, in the case of Florian Havemann who was only 16, "educational measures".
The shock was all the greater because of the prominent part in the protest played by the eldest daughter of a committed academic member of the "Ideology Commission".
That never happened, but he did win other – possibly less prestigious – awards from the government over the next couple of decades, and it soon became apparent that removal from the Institute for Marxism–Leninism would not mark the end of his academic career.
[1] He also served, between 1979 and 1990, as director of the Weimar based business "Hermann Böhlaus Nachfolger" publishing operation which had, in effect, functioned as a subsidiary of the Akademie Verlag since becoming cut off from its Vienna holding company by the so-called "Iron Curtain".
[2] He nevertheless worked actively with the "Marxist working group on the history of the German labour movement" ("Marxistische Arbeitskreis zur Geschichte der deutschen Arbeiterbewegung") which functioned under the auspices of Party of Democratic Socialism (PDS), which was emerging as a new formulation, for a democratic Germany, of East Germany's old Socialist Unity Party (SED), which itself was by now widely (though by no means universally) discredited and disparaged.
[1] Between 1963 and 1966 Lothar Berthold served as secretary to the authors' collective, mandated to compile and produce an eight-volume history of the German labour movement.
[2][11] Also worth highlighting in Berthold's two-volume biography of Ernst Thälmann, the hardline Stalinist leader of the Communist Party between 1925 and 1933 who was later killed by the Nazis after eleven years detained in solitary confinement.
[14] Comrades attributed great political value to the biography, seen as a reason why Berthold won the National Prize of the German Democratic Republic not once but twice.