The double infant Jesus The double infant Jesus

On the steps (lat. gradus) to the altar the cantor recited Gregorian chants during mass. They were collected in a chorale book for the liturgy, the so-called gradual.
Only seven sheets of the large-format gradual have survived. They are each decorated with an initial, in the internal space of which there is a figurative representation. Each staff has five red lines with black square notes on them. Below is the Latin text of the chants.
On Christmas Day, the Introitus Puer natus est (“A child is born to us”) rang out at the entrance to the mass. The text is based on a passage from the book of Isaiah in the Old Testament. There the birth of the Messiah is predicted.
In the internal space of the initial P, Mary rests in front of a brick stable; a maid gives her a drink to refresh her. Christ even appears twice: between ox and donkey and in the arms of the visitor, maybe a depiction of Jesus' double-nature.