THE FIRST PART OF THE MASS
The Public Preparation at the Foot of the Altar
This first part of the Mass contains three things 1. The desire to go up to the altar with confidence in God’s good will. 2. The confession of one’s faults. 3. Prayers to obtain their remission and the grace to ascend the altar with complete purity. These preparatory prayers take place at the foot of the altar, or often at a slight distance from the altar, since they are meant as a preparation for going there. They are mentioned in the Missals only very rarely, and are absent entirely from the first Roman Orders. The six ancient Orders printed by Fr. Mabillon tell us that the bishop, after dressing in the sacristy and signaling the choir to chant the Introit psalm, went first to the head of the choir with all his officers; that he made a bow there, made a sign of the cross on his front, gave a sign of peace to his officers, and stood for some time in prayer before making the sign to the chanter to say the Gloria Patri; that then he advanced to the steps of the altar, and there asks pardon for his sins; that the ministers, except for the acolytes and thurifers, remain kneeling and praying with him; and that he continued to pray until the repetition of the Introit verse.
None of these ancient Ordines describes the prayers of the preparation. In the Latin Church they are not found in writing before the ninth century, being left to the private devotion of the bishops and priests to say them either individually and silently or with the other ministers. No council or pope prescribed the form or terms of these prayers, any more than the moment when they should take place. Some have performed them in a particular chapel, as it is done today at Tours at the tomb of St. Martin; others do it in the choir, as at Laon and Chartres, or at the entrance of the sanctuary, far from the altar, as at Soissons and Châlons-sur-Marne; others at the left or Gospel side of the altar upon entering, as the Carthusians who have taken many of their usages from Vienne and Grenoble; finally, others do them in the sacristy, as at Reims. Various bishops have determined the place they are to be said and used whatever prayers were convenient for their devotion. This is why these prayers differ in their wording and content. Since the ninth century they have been included in some Missals, and more commonly in Pontificals, Manuals, or Ordinaries of the churches. We must look for them there, at least until the 14th century.
These preparatory prayers pertain as much to the assistants as to the priest, and they are said publicly at the foot of the altar, so that no one need assist at Mass without preparation.
 Pertransit Pontifex in caput scholae et inclinat caput ad altare, surgens et orans (Ordo Romanus I; Mus. Ital. p. 8) In caput scholae et in gradu superiore (Ordo Romanus II; p. 43); In tribunal Ecclesiae (Ordo Romanus III; p. 56).
 Non prolixa completa oratione… annuat cantori ut Gloria dicat: ipse vero ductus a diaconibus pergat ante altare, inclinatisque ad orationem cunctis, stantibus acolythis cum candelabris et thuribilus, etc (Ordo Romanus V; p. 66).
 Inclinans se Deum pro peccatis suis deprecetur (Ordo VI; p. 71).
 Pontifex orat super ipsum oratorium [prie-Dieu] usque ad repetitionem versus (Ordo I; p. 8). Stat semper inclinatus usque ad versum prophetalem (Ord. II; p. 43).
 Pontifex concelebrat interim secreto orationem ante altare inclinatus (Ord. III; p. 56).