For a long time the bull was read as the document that opened the European witch trials. Nineteenth century historians placed it at the head of the story, and the placement was natural: it is the earliest papal text most readers meet on the subject, it names real provinces, and it describes accusations that were really being made. Modern work has narrowed the claim a great deal. Trials for maleficium were already running in the western Alps decades before 1484, the theological apparatus that turned a witch into a member of a diabolical sect was assembled in the 1430s, and the great wave of prosecutions came a century later and was overwhelmingly the work of secular courts rather than church ones.
What the bull did contribute was a name and a seal. Bound at the front of the Malleus Maleficarum from 1487, it travelled with the book through more than twenty printings and lent papal weight to a text Kramer wrote largely alone, from which Sprenger appears later to have kept his distance, and which the theology faculty at Cologne endorsed in terms considerably weaker than the printed approbation suggests. Whether that approbation was tampered with in the printing house is still argued.
The instrument and the book are separate subjects and the atlas keeps them apart. The bull is a short administrative act about jurisdiction in five German provinces. The Malleus is a long argument about how to find and convict a witch. The trials drew on the second far more than on the first.