The design of the gilded bronze urns, created to hold the keys that open and close the Holy Doors, stems from an intuition of artistic director Paolo Poli: each casket was to reflect the beauty and meaning already present in the door it is associated with.
From this idea emerged surface patterns that evoke the artistic decorations of the great doors, without reproducing them literally. In this way, the symbolic bond between the doors and the urns that hold their keys has been reinforced.