Freya von Moltke, who has died aged 98, was a co-founder of the group of German anti-Nazi activists known as the Kreisau Circle, and hosted a series of three conferences which, for most of the participants, had fatal consequences.
She founded the Kreisau Circle with her husband, Helmuth James Graf von Moltke, and their close friends Peter Graf Yorck von Wartenburg and his wife Marion. All of them had opposed Hitler from the outset, and the group's name was taken from the von Moltkes' Silesian estate where their conferences were held in May and October 1942 and in June 1943.
Born Freya Deichmann in Cologne on March 29 1911, she was the daughter of Carl Theodor Deichmann, a banker. She first met her future husband in 1929 at the University of Breslau, where she was helping him as a researcher before commencing her own studies for a Law degree at the University of Bonn.
He was the great-grandnephew of Field Marshal Helmuth von Moltke, Chief of the General Staff of the Prussian army in Bismarck's time, and thus bore one of the most illustrious names from Germany's military past. He and Freya married in 1931.
In 1935 – the year in which Freya completed her doctorate in Law – Helmuth von Moltke, whose parents were Christian Scientists, refused a judicial appointment, because accepting would have entailed joining the National Socialist Party. Instead he opened an international law practice in Berlin, and, always a great admirer of British traditions, started studying to qualify in English Law as a Rhodes scholar at Oxford.
Freya gave birth to their first son, Caspar Helmuth, in 1937, and thereafter lived at Kreisau, on the family estate which her husband inherited two years later. A second son, Conrad, was born in 1941.
Before the war Helmuth von Moltke was a regular visitor to Britain, and in the summer of 1939 he was one of several German opponents of the Führer who personally sought to warn Chamberlain, Halifax, Churchill and any other British leaders who would listen about Hitler's plans to attack Poland at the end of August.
As soon as war did break out, Graf von Moltke was drafted into the German counter-intelligence service, gathering military intelligence from foreign sources and, vainly, preparing appraisals on questions of international law. Most of his advice was simply ignored.
As he made clear in letters home to his wife, he was increasingly appalled at what he saw and heard of Germany's conduct of the war and its treatment of the populations in the countries it had overrun.
Von Moltke was in contact with a wide range of similarly dismayed Germans in Berlin. Those he and Yorck von Wartenburg invited to the Kreisau estate conferences included two Jesuit priests; two Lutheran pastors; political conservatives, liberals and socialists; landowners and former trade unionists.
Almost all the men involved were to pay with their lives, though their discussions were concerned not with planning Hitler's overthrow – which they had little notion how to achieve – but with the economic, social and spiritual foundations of the new society which they hoped would come into existence once Hitler had departed the scene.
Even so, von Moltke asked his wife to hide the conference reports in a place even he should not know. She preserved them, with his letters, in her beehives.
Although von Moltke (who opposed assassination) and Yorck argued for a coup to unseat Hitler, they had neither the arms nor the access to the Führer to bring it about. Essentially the Kreisau Circle was more discussion group than conspiracy; but they, and their contacts with other more practical opposition groups, were already being watched by the Gestapo.
Von Moltke was arrested at Himmler's instigation in January 1944. Although Freya was at first able to visit him, the situation changed on July 20 1944, with the failed assassination attempt by Claus Schenk Graf von Stauffenberg. The Gestapo seized on the pretext to eliminate all opposition, and in January 1945 von Moltke went on trial before Roland Freisler's people's court (Volksgerichthof).
There being no evidence that von Moltke had been part of Stauffenberg's plot, Freisler held that his having even discussed a Germany based on moral and democratic principles constituted treason. Von Moltke was sentenced to death and executed.
Freya and Marion Yorck (whose husband was also executed) fled Kreisau and evacuated their families to Czechoslovakia to await the war's end, when Kreisau was ceded to Poland and British friends helped Freya leave for South Africa with her two sons.
There she worked as a social worker and as a therapist for the disabled, but in 1956, unable to tolerate apartheid, she returned to Berlin, where she proceeded to publicise the Kreisau Circle.
In 1960 she moved to Norwich, Vermont, to be close to the social philosopher Eugen Rosenstock-Huessy, who died in 1973. She transcribed her husband's 1,600 letters, which were published as Letters to Freya in 1988 and won the Geschwister Scholl literary prize.
She took American citizenship in 1975, but was delighted that Kreisau was chosen as the venue for a ceremony of German-Polish reconciliation. She supported a foundation opened in her name to perpetuate the Kreisau Circle's principles.
Freya von Moltke died in Vermont on New Year's Day. Her sons survive her.