During the Middle Ages, the "Donation" was widely accepted as authentic, although Emperor Otto III did possibly raise suspicions of the document "in letters of gold" as a forgery, in making a gift to the See of Rome. It was not until the mid-15th century, with the revival of Classical scholarship and textual criticism, that humanists, and eventually the papal bureaucracy, began to realize that the document could not possibly be genuine. Cardinal Nicholas of Cusa declared it to be a forgery and spoke of it as an apocryphal work.