[1] He made a particularly noteworthy contribution with his two-volume biography of Otto von Bismarck[2] which in the view of at least one commentator represented a paradigm shift for historiography in the German Democratic Republic.

[4] The family was politically aware, and even as an old man Wilhelm Engelberg delighted to proclaim himself a "democrat of 1848" ("Ich bin 48er Demokrat").

[5] By the time his dissertation was completed, however, in 1934, régime change had come to Germany, and his old history tutor, Gustav Mayer (who was Jewish), had been sacked from his university posts and persuaded to emigrate to (at this stage) the Netherlands.

[5] A few days after the traditional ceremony held on 22 February 1934 in which Engelberg orally defended his work before a committee of examiners Nemesis followed, however.

[5] On the evening 26 February he was arrested, and faced the régime's usual charge in such cases: Conspiracy to Commit High Treason.

[5] He later told his son that he had considered himself lucky: if the Nazis had known that Engelberg was the Communist Party student leader identified with the cover name "Alfred", his sentence would have been spent not in a prison but in a concentration camp.

[5] The war ended in May 1945, but Engelberg, like many, encountered what sources term bureaucratic delays in attempting to return to what remained of Germany.

In the end he succeeded in returning to Germany via Italy and Switzerland early in 1948,[9] which was too late to renew his relationship with his father, Wilhelm Engelberg, who had died the previous year.

The next year, 1949, Ernst Engelberg was appointed Professor for the "History of the German Labour Movement" at Leipzig University, where colleagues included Hans Mayer (an old comrade from their time in Geneva), Ernst Bloch and Walter Markov,[10] along with Werner Krauß, Wieland Herzfelde and Hermann Budzislawski.

[3] Engelberg was impressed by Bismarck's political realism, his intellectual insights and imagination, the care with which he calibrated his foreign policy, and his willingness to recognise the emergence of the new age.