Why did goethe marry Christiane Vulpius, his companion of eighteen years, on 19 October 1806, five days after Napoleon's victory over Prussia at the battle of Jena-Auerstedt? The act perplexed Weimar gossips at the time, angering some, and Goethe's motives for suddenly marrying then have been much discussed since.

After the wedding, a legend rapidly jelled: that the poet had married Christiane primarily out of gratitude, to thank her for her valiant defense of his person and home from the French soldiery plundering Weimar on the “schreckliche Nacht” of 14 October. One report, by the Jena anatomist J. C. Loder, can stand for several:

This explanation (a dominant one in the literature until about 1950, and still recycled in its more popular strains) appears to have been set into circulation by Goethe himself, who cites gratitude as a catalyst for his decision in a letter of 17 October to Wilhelm Christoph Günther (the court chaplain of the Jakobskirche in Weimar) requesting that Günther officiate at his wedding on the 19th.