With his elder brother László, István grew up in a prosperous liberal-Jewish family and acquired a sold classical education, largely free of Jewish religious elements.
[1] He later wrote that it was as a result of observing the material hardship of his own family's domestic servants, of reading the works of writers such as Émile Zola and Friedrich Nietzsche, and of the senseless carnage of the First World War battlefields that his political awareness was triggered while he was still at school.
Szende moved in socialist left-wing circles in which membership of the Social Democratic Party provided a mantle of acceptability for his continuing interest in Marxist philosophy, an area in which by now he was also lecturing.
On a second occasion, he was arrested for "inciting class hatred" in a lecture delivered to members of the Metal Workers' Trades Union, and accused of "insulting the national honour" in another article.
By this time his widowed mother and brother had distanced themselves from his political activity, and while they remained in Hungary, Stefan Szende, now in enforced exile, was stripped of his Hungarian nationality.
The two of them married in 1929 and moved into a two-room city apartment, still receiving some financial support from International Red Aid, supplemented by occasional payments for published articles.
He was not hugely active within the PO, but he nevertheless later recalled that his time in it had provided a welcome release from the "social fascism precepts" ("Sozialfaschismusthese") characteristic of the mainstream communist parties as politics became more polarised.
Stefan Szende, along with Jacob Walcher, Paul Frölich and August Enderle, was among approximately 1,000 members who transferred from the KPO to the new Socialist Workers' Party ("Sozialistische Arbeiterpartei Deutschlands" / SAPD).
[5] The Nazi take-over at the start of 1933 completely changed the political backdrop, and after the Reichstag fire at the end of February 1933 the new government accelerated the transformation of Germany into a one-party dictatorship.
Having already anticipated that the period of Nazi government would be no passing trend, but a sustained and long-term threat, the SAPD was in many ways better prepared to transform itself into an underground movement than the larger Communist Party and SPD.
Since Szende was both the leader, for Berlin, of the illegal SAPD and a foreign stateless Jew, he was in particular danger from the sinister fantastical obsessions of his captors.Those arrested were taken to the "Maikowski House", a former trades union building in Berlin-Charlottenburg which had been taken over as a head office by local Nazi para-militaries (SA).
[1] On 1 December 1933 the SAPD prisoners were transferred to the "Columbia House" concentration camp at Berlin-Tempelhof where nightly torture sessions by the SS guards were part of the routine.
By this time he was suffering not merely from the daily beatings at the concentration camp, but also from the long term injuries to his genitals, which were treated cruelly and painfully with Silver nitrite by a doctor who was entirely open in sharing his conviction that his patient was a member of the International Jewish Conspiracy.
[1] Christmas 1933 and the new year holiday passed largely unremarked, but on 5 January 1934 the prisoners were moved again, now to the newly opened Oranienburg concentration camp a short distance to the north of the city.
The day after Szende's transfer to Oranienburg, Erszi wrote a letter to the Hungarian consul in Berlin, pleading for help in arranging permission for her to visit her husband whom she probably had not seen since his arrest the previous autumn.
[6]} In several of his subsequent published writings, Stefan Szende describes in considerable detail the extreme sadistic pleasure taken by Obersturmführer Hans Stahlkopf in the regular torture sessions.
In some of the other concentration camp guards and administrators it was occasionally possible to detect glimpses of humanity beyond the inhuman cruelty, but Stahlkopf was driven by a passionate antisemitism and took an unconfined delight in inflicting physical pain.
Brandt organised a letter, signed by a number of Norwegian lawyers, in which the dubious legal basis for the charge leading to a possible death sentence was stressed.
The Hungarian consulate had issued him with a passport, but returning to Hungary was out of the question because of the circumstances under which he had left the country – with the threat of an imminent prison sentence hanging over him – back in 1928.
He found he had become something of an iconic figure among party comrades as someone who had survived Gestapo detention and Nazi imprisonment and was already able to relate and write down his experiences with an unusual degree of precision.
The extent of their poverty was barely dented by occasional payments for articles that Stefan Szende contributed to German-language newspapers such as the Prager Tagblatt, Der Sozialdemokrat and Die Neue Weltbühne.
Early on he obtained work presenting – in Swedish – a course on Socialism to a group of workers in the food sector, which enabled and required him rapidly to enhance his mastery of the language.
One of his books, "Wohlstand, Frieden und Sicherheit" ("Welfare, Peace and Security") was adopted as a teaching text by the Swedish Education Organisation and used in secondary schools.
How Stefan Szende found out what was happening is not known, but after many years during which he had no contact with the relatives he had left behind, he telegraphed his sister in law and his mother from Stockholm, promising to do everything necessary to obtain visas for them so that they might travel to Sweden.
The former communist Stefan Szende was now officially a Social Democrat, influenced by his experience and a conviction of a need for unity on the political left within which, implicitly, Soviet-style communism had no part to play.
After the war ended, formally in May 1945, Stefan Szende reportedly received several lucrative offers to return to Germany and become an editor in chief or publisher of a newspaper, or even a government minister.
He preferred to preserve his independence and freedom, however, notably in respect of his fifteen-year-old daughter, and in the end the family stayed in Sweden, unlike Szende's friend Willy Brandt.
Work for RIAS, friendship with Willy Brandt and his own itinerant past all combined to give him a firm connection with West Berlin, which endured through the rest of his life.
In 1975 Stefan Szende published a memoire entitled "Zwischen Gewalt und Toleranz" ("Between Violence and Tolerance"), recalling life experiences and also extending to more theoretical reflections on personal and political development.
His unusually varied life story had left him as a committed European, keen to bridge differences between competing political blocks, but resolutely separated from the Soviet bloc.