Odgovor je zanimljiv - kletvom! Naime, na Got Medieval blogu piše da su mnoge knjige počinjale kletvom poput:
In the name of the Father and the Son and the Holy Spirit, Amen. In the one thousand two hundred twenty-ninth year from the incarnation of our Lord, Peter, of all monks the least significant, gave this book to the [Benedictine monastery of the] most blessed martyr, St. Quentin. If anyone should steal it, let him know that on the Day of Judgment the most sainted martyr himself will be the accuser against him before the face of our Lord Jesus Christ.
Should anyone by craft of any device whatever abstract this book from this place may his soul suffer, in retribution for what he has done, and may his name be erased from the book of the living and not recorded among the Blessed.