There, he became acquainted with members of the "Ibsenklub" (named after the playwright, Henrik Ibsen); a group of liberal young people who met to exchange ideas, about modern literature that had an aura of "mystery and scandal".
[1] Based on his correspondence, this led to a brief affair with Margarethe Gütschow [de], who later became an archaeologist, and an equally brief engagement to one of her cousins.
This network of relationships also led to a group trip to Paris, during which he began an affair with the painter, Maria Schorer.
In that capacity, he was involved as a middleman in the controversial sale of the wax bust, Flora, which was purchased by the Bode Museum in Berlin, from the English art dealer Murray Marks (1840-1918), in the belief that it was by Da Vinci.
It is generally assumed that Gretor served as the prototype for the title character in Wedekind's play, The Marquis of Keith.