 The theme was partly inspired by the editors' historical interests and partly from Lovecraft's extrapolations of frightening pasts for humanity that extended back to the Paleolithic and even further.This was a popular theme in "Weird Tales" at the time and used by many other authors, including Robert E. Howard and Clark Ashton Smith.“Found in a Trunk from Extremadura” was first published as “Manuscrit trouvé dans une malle d'Estrémadure” in the French anthology "HPL 2007".