Having discussed the various sacramentaries in the last installment, let's move on to a typical papal "stational" Mass. The term "stational" here refers to the fact that the various churches in Rome were called "stations" and the pope would go from church to church, each on a different Sunday, to celebrate Mass. The reason for looking at this Mass is that is was fairly stable for nearly 100 years. Because of this stability it was well documented, especially so since a priest at each church would need to prepare for the papal Mass.
The pope travels from his "patriarchium" (think throne) at the Lateran Palace for all Masses. He is accompanied by the entire papal court: the defensores (legal administrators of Church property in Rome), the seven deacons from the seven regions of Rome (on horseback) each of whom has an appointed sub-deacon as an assistant, the chief dignitaries of the Apostolic Palace (also on horseback). At the entrance to the Church the pope is met my the Master of Ceremonies. the rest of the clergy will have already entered the church and will be seated on benches that run around the sanctuary, somewhat like the later choir-stalls would. The cathedra or bishops chair is placed in a prominent spot and is raised above the rest. The pope vest in the sacristy which is built near the main entrance to the church. He puts on alb, cincture, stole, tunicle, episcopal dalmatic (the dalmatic is the deacon's vestment, and this reminds him of his first call to service) and finally the chasuble. Note that at this time all clerics, even the acolytes, wore a chasuble! Finally he puts on the pallium, a white woolen cloth that represents his authority as the metropolitan bishop.
The Gospel book is carried by an acolyte to the altar. He is accompanied by a sub-deacon. Note that the book is not carried bare-handed, but the acolyte covers his hands with what today would be called the humeral veil, although a lightweight white one worn by bishops assistants.
Finally, when all are ready, the pope takes his maniple and waves it as a signal to start. All stand and the Introit is sung. Preceding the pope are seven torches carried by seven acolytes and fire carried in a brazier (this was an honor originally rendered only to the emperor). The two deacons assisting the pope kiss his hands, and assist him in walking. This is carried over from the Orient.
The processions pauses as two acolytes bring a box (capsae) that contains a fragment of the Blessed Sacrament that has been reserved. The pope makes a profound bow to the Blessed Sacrament and then continues to the altar. After reverencing the altar and signing himself, the pope shares the sign of peace with a bishop, a priest, and the deacons. At a signal from the pope, the introit is concluded with the "Glory be to the Father..." and a repetition of the antiphon. The pope then prostrates himself on a specially laid-out carpet and prays silently. When he rises the Gospel book is brought to him and he kisses it. The choir begins to sing the Kyrie eleison ("Lord have mercy") while the pope goes to his cathedra and stands facing the East. Again, he signals the choir (actually, the schola) when to stop. He then turns and greets the congregation saying "Peace be with you." ("Pax vobis.") then sings the oration to which all respond: "Amen."
All in the sanctuary sit (the rest of the church has no seats so the people remain standing). The subdeacon goes to the ambo and reads the epistle after which a cantor goes to the ambo and, alternating with the schola, sings the gradual and, as needed, the alleluia or tract. When this is done the deacon goes to the cathedra, kisses the foot of the pope, and asks for his blessing. he then takes the Book of the Gospels and, accompanied by two acolytes with candles, goes to the ambo where he chants the Gospel. At its conclusion, the sub-deacon takes the book (again using the humeral veil) and takes to each of the priests who kiss it. He then hands it to an acolyte who immediately returns it to the Lateran Palace! There is no sermon nor is there a dismissal of the catechumens.
The pope stands and proclaims "The Lord be with you." (Dominus vobiscum.) and intones "Let us pray." (Oremus) -- but no prayer follows. Instead, they begin the preparations for the Liturgy of the Eucharist. This begins by dressing the altar (it has been bare up to now). An acolyte brings a chalice on which lies the folded corporal. The deacon takes this, puts it at the right of the altar, and then with the help of a second deacon opens the corporal (this cloth was much longer than today's corporals, probably covering the entire length of the altar). The gifts are brought forward and the pope takes the bread while the archdeacon (a priest) takes the wine. The remaining priests collect whatever other offerings are made. The chalice is placed on the altar and the archdeacon, signaled by the pope, arranges the bread to be consecrated. One of the schola members adds water to the wine. When all is ready, the pope goes to the altar of places his offering there and then receives the offerings of the other clergy.
Since there is some confusion about this, I will cite this next part directly from Jungmann: "Then begins the canon, taking the word in the comprehensive meaning it then had. Each one has taken his appointed place. Normally that would mean that the pope, coming from his cathedra, would stand behind the altar facing the people -- for the church usually was not oriented in our sense, but 'occidented,' the entrance towards the East. Behind the pope and forming a row on the axis of the church back toward the throne, stand the bishops and perhaps the priests also. to the right and left of the pope and in front of the bishops, the deacons are ranged, and behind them the acolytes. The subdeacons are on the other side of the altar opposite the pontiff. During the canon there is no further change externally. "The pope begins the prayer in a loud voice. The subdeacons respond to the introductory versicles and take up the singing of the Sanctus. The pope alone stands one more erect and continues the prayer, while the others remain bowed. The words of consecration, like all the other parts of the canon, are said audibly; otherwise there is nothing distinctive about them. At the 'Nobis Quoque' the subdeacons straighten up and make read for the ceremony of breaking the Bread; the paten for this has already been brought up at the start of the canon. At the Per quem haec omina the archdeacon too straightens up; when the pope elevates the Host in the sight of all and recites the final doxology, it is the archdeacon's duty to take the chalice by the handles and lift it, too, on high. The canon is therefore quite simple and free of any other display. The actio, as it is termed, simply presents the pontiff's sacramental word, with no ornament other than his prayer. Even the succeeding Lord's Prayer (Pater noster) with its appended embolism, does not break into the picture, at least since Gregory the Great had it fixed immediately after the canon."
Following this there is another Kiss of Peace (Pax Domini) which is shared among all present. The fraction rite then takes place with the pope breaking the Bread, placing one fragment on a paten that is handed to him. The Precious Blood is removed, and the remaining bread taken to the other priests who continue the breaking while the pope returns to his cathedra. When all the bread is broken, the paten with the fragment on it is brought to the pope who breaks off a small piece and places it in the chalice. He consumes the remainder and, assisted by the archdeacon, receives the Precious Blood. The archdeacon then makes the announcements since those not receiving communion could now leave (not much has changed!).
Communion for the clergy and people now follows. When all who desire have received, the pope goes to the altar and intones the Postcommunion prayer. At a signal from the pope a specially chosen deacon sings the "Ite missa est" ("Go, the Mass is ended") to which the people respond "Deo gratias" ("Thanks be to God"). The procession then forms for the return to the sacristy.