The function of the upstairs part of the west facade is not entirely clear. The right of baptism (long reserved for the Collegiate Church of Mary) was at a baptismal font, which was behind the marble throne, until the end of the Ancien Régime. Possibly the space was involved in these ceremonies. Furthermore, in the western wall, under the great west window, there is a Fensetella (small window) even today, through which there is line of sight to the court below, the former atrium. It is certain that the so-called Carolingian Passage entered this room on its northern wall, connecting the Aula Regia (King's Hall) in the north of the palace with the church.
