New documentary evidence throws light on the genesis of Das unauslöschliche Siegel and on Langgässer's narrative techniques. Her hitherto unpublished notes on Donoso prove that the extensive quotations from his works in the “Turm-Kapitel” derive from one source: L. Fischer's introduction to his translation of the Ensayo sobre el calolicismo. Further evidence supplied by her widower shows that she wrote the chapter before 1944, and that its mise-en-scène was prefigured in her visit to Senlis, France, in 1937. Thus, the hypothesis is untenable that—as an attempt at self-justification in the face of charges of manichaeism—she inserted the chapter only after she had completed the rest of the novel. It seems probable that Langgässer considered Donoso's life exemplary from a Christian viewpoint, and that her montage of his writings stemmed from her desire to create a “new form” for the Christian novel. Donoso's religious beliefs and his hostility to the Enlightenment not only provide appropriate material for the chapter (the “counterpointing” of religious, cultural, and political events in Europe over a period of several centuries), but also reflect Langgasser's own religious attitudes, which any critical appreciation of the novel as a whole must take into account.