Another group, which had formed links with various links with various resistance movements including the Kreisau Circle and whose membership sometimes overlapped, was known as the Solf Circle. Strictly speaking the people who gathered at the home of Hanna Solf, widow of German Ambassador to Japan, Dr Wilhelm Solf, were not a resistance group. They were a group of intellectuals, diplomats, businessmen and former politicians who met to enjoy the company of like minded people, safe in the knowledge that they were not in danger of being overheard and denounced by fanatical neighbours. They included Nikolaus von Halem, a lawyer and former civil servant, and Reichstag Legation Secretary Herbert Mumm von Schwartzenstein who both had links with Communist resistance leader Josef 'Beppor' Romer; diplomat Otto Kiep; Count Albrecht von Bernstorff, nephew of the German ambassador to the United States during the First World War; educationalist Elisabeth von Thadden who ran a school for girls near Heidelberg; Countess Hanna von Bredow, the granddaughter of Bismarck; Father Erxleben, a Jesuit priest, and Hanna Solf's daughter, Countess Ballestrem.

The Solf Circle consisted of a group of like-minded people who simply wished to oppose and counter the oppression, persecution, humiliation and degradation of human beings by the regime. It included Graf von Bernstorff, Fanny von Kurowsky, Imgard Zarden, Dr Herbert Mumm von Schwarzenstein (retired Legation Counsellor), Dr Otto Kiep (Minister in the Foreign Service), Dr Hilger van Scherpenberg (Legation Counsellor) and Elisabeth von Thadden. They used to meet in the house of Frau Hanna Solf, widow of Dr Wilhelm Solf who had been German Ambassador in Tokyo and had died in 1936. They were all arrested in 1944, some as having been present at a tea party given by Fraulein von Thadden on 10 September 1943 when certain statements hostile to the regime had been made, some merely because they were members of the circle. Certain of them were subsequently executed, simply because they had stood up for humanity.

In September 1944, the Nazis murdered the teacher Elisabeth von Thadden, the aunt of Der Spiegel editor Marianne Wellershoff. She had been denounced by a man named Paul Reckzeh, who had spied on a tea party on behalf of the Gestapo in 1943. Von Thadden was at that tea party. She met regularly with several other academics who were critical of Adolf Hitler's regime, a group centered around the resistance fighter Hanna Solf.

The betrayal of the Solf Circle and the death sentence given to Elisabeth von Thadden by the People's Court, as the Nazi regime's extra-judicial court was called, was a frequent topic of discussion in Wellershoff's family and a source of trauma for her mother Maria. That led Wellershoff to interview Irmgard Ruppel, née Zarden, during a visit to New York in 1995 -- Ruppel had attended the fateful tea party decades before emigrating to the United States. When Wellershoff began looking into Paul Reckzeh for the current issue of Der Spiegel Geschichte, the history periodical published by Der Spiegel, she found the cassette with the unpublished interview. Ruppel was no longer able to authorize the interview prior to publication: She passed away in 2018. Reckzeh died in 1996 in Hamburg.

DER SPIEGEL: Ms. Ruppel, you met Elisabeth von Thadden for the first time in 1937 when you started going to her Protestant boarding school in Wieblingen, a district of the southern German city of Heidelberg. Why did your parents send you there all the way from Berlin?

Ruppel: My mother wanted me to learn how to cook and my parents knew that Elisabeth von Thadden opposed the National Socialists. She was a remarkable woman and her boarding school had a very good reputation. She had a background in social welfare. But I wasn't part of Thadden's inner circle and my time there wasn't some kind of life-changing experience. I just had a nice year there.

DER SPIEGEL: How did Elisabeth von Thadden's critical position towards the Nazis make itself apparent?

Ruppel: It wasn't constantly brought up, but the school was extremely pious and Protestant. The Heidelberg pastor Hermann Maas was a good friend of hers and he also did a lot for the Jews in the region -- as far as one could do anything. We also sometimes went to his church. The Nazis were suspicious of Thadden because she didn't try to hide her rejection of National Socialism. For example, I can't remember there being a chapter of the League of German Girls (the girl's wing of the Hitler Youth) at the boarding school. Her stance is also the reason why the school was ultimately closed. She was a very respectable person.

DER SPIEGEL: Did you maintain contact with Elisabeth von Thadden following your year at the Wiebling boarding school?

Ruppel: My parents had contact with her during the war. After the Nazis closed her school, she came to Berlin and lived with her friend Anna von Gierke, a well-known politician and social worker.

DER SPIEGEL: Then she invited people to a tea party on September 21, 1943, on the occasion of the 50th birthday of her sister, Anza Braune.

Ruppel: Yes, it was a group who all knew one another and who shared the same general world view: Hanna Solf, who lived in our building in Alsenstrasse, my father Arthur Zarden, Hilger van Sherpenberg, Otto Kiep, Richard Künzer. And then the elderly Fanny von Kurowski, whose father had been a cabinet member of Bismarck's during the time of the Congress of Berlin in the late 1870s -- quite a while ago.

DER SPIEGEL: And then there was another guest.

Ruppel: Yes, Paul Reckzeh. He had called Thadden the day before. She had a very good friend in Switzerland, the daughter of the painter Segantini. This daughter knew Reckzeh's father, a professor of medicine in Berlin. The Reckzehs always went on vacation in Sils Maria in Switzerland, so the families had known each other for a long time. Paul Reckzeh mentioned this when he called Thadden.

DER SPIEGEL: What did he say?

Ruppel: That Ms. Segantini kindly requested her to introduce him to people who had similar views in Berlin. Later, of course, Ms. Segantini felt horribly guilty about having sent this horrific criminal into the home of her friend. But Thadden should also have been immediately suspicious: How is it possible that a young man in the fall of 1943 is traveling to Switzerland? He should have been at the front!

DER SPIEGEL: But the conversation didn't raise any red flags for her?

Ruppel: No. She said: I'm having a tea party tomorrow, why don't you come too?

DER SPIEGEL: It was the return invitation for the many times she had been hosted by resistance activist Hannah Solf, in whose apartment academic and aristocratic regime critics would meet and discuss. Your father, Arthur Zarden, who was state secretary in the Reich Ministry of Finance during the Weimar Republic, was a member of the Solf Circle. Were you?

Ruppel: No, I was working in a nearby office and merely picked up my father at Thadden's party on that 21st of September, 1943. I was not there very long, maybe half an hour, but they were almost all still there. I also didn't say much. I was 21 years old and the guests were all much older. It's unfortunate that Thadden had invited precisely these people that afternoon. If Reckzeh had only spoken with her, it might not have been so bad.

DER SPIEGEL: Do you remember Reckzeh?

Ruppel: I remember a young man, not even 30 years old, with a rather flabby face. Pretty average appearance. He was heavily involved in the conversations. Even though people were otherwise so incredibly careful with people they didn't know, nobody that afternoon seemed to wonder who he actually was.

DER SPIEGEL: What was the conversation about?

Ruppel: Unfortunately, the conversation immediately turned to the fall of Italy, the overthrow and arrest of Mussolini and what it might mean for the course of the war. Back then, even the smallest doubts about Germany's ultimate victory was considered high treason. Reckzeh took part in the conversation and then said: I'll soon be heading back to Switzerland and if you have any letters for your friends there, I'd be happy to take them and mail them from Switzerland.

DER SPIEGEL: Did you find that suspicious?

Ruppel: When my father and I were heading home, he immediately said: "I wish I hadn't come. I thought that man was odd." He had immediately noticed that something wasn't quite right, but it would also have been strange if he had left immediately. For a time, nothing happened. But we all noticed that our telephone calls were being monitored, because it was a rather primitive technology and you could hear it clicking.

DER SPIEGEL: Did that confirm your suspicion that something wasn't right about Reckzeh?

Ruppel: We heard via Helmuth von Moltke, who worked in military intelligence, that Reckzeh was a Gestapo informant. In mid-October, Reckzeh called us and said he was soon going to be travelling to Switzerland again and asked if he could drop by. He would be happy, he said, to take letters with him again and mail them in Switzerland. I told my father that it would have been wrong to turn down the visit. So he answered: "Come by on Sunday morning." I was also there, and we had a nice conversation. My father said he had a friend in Lugano to whom he sometimes wrote, but that it was fine if the censors read it. But Reckzeh continued pushing: He was an agent provocateur.

DER SPIEGEL: What happened then?

Ruppel: November came, and then December, but we didn't hear anything and started thinking the Gestapo might have other things to do. But they were, of course, still monitoring the situation. Then, on Jan. 12, 1944, everyone who was at the tea party was arrested. Despite the fact that, in contrast to the July 20, 1944 conspirators (the group around Claus von Stauffenberg that attempted to assassinate Hitler), none of those arrested had been in a position to carry out a violent act against the Third Reich.

DER SPIEGEL: Moltke was also arrested, because he had informed Otto Kiep that Reckzeh worked for the Gestapo. Elisabeth von Thadden was arrested that same day in France.

Ruppel: Yes, she had been given a low-ranking position there with the Red Cross that was far below her capabilities. She was subjected to significant harassment. I never saw my father again. He committed suicide a few days after the arrest by jumping out of the window at Joachim Friedrich Strasse 2 on January 18. That was a Gestapo building near Kurfürstendamm, where we were interrogated.

DER SPIEGEL: What took place there?

Ruppel: Criminal Investigator Herbert Lange led the investigation. He was known for horribly torturing prisoners, but I wasn't aware of that. And us women weren't subjected to torture. The interrogations were nothing but a fishing expedition. The Gestapo had nothing on us, because there wasn't anything to be had. They arrested all of us and then wanted to construct something out of the interrogations. I said: "High treason? What is that supposed to mean? That was no high treason, it was just a few retired people talking about the events of the day."

DER SPIEGEL: How did you find out about your father's suicide?

Ruppel: Lange told me about it. He was very, very, very uncomfortable. In response, I threw a tantrum and said: "I'm going to survive all this, but you won't!" I always found it surprising that this never had negative consequences for me. But Lange simply ignored it.