A Papal Mass is the Solemn Pontifical High Mass celebrated by the Pope. It is celebrated on such occasions as a papal coronation, an ex cathedra pronouncement, the canonization of a saint, on Easter or Christmas or other major feast days.
Until the 1960s, there were numerous special ceremonials that were particular to the pope. Many have fallen out of use; some were last celebrated by Pope Pius X (reigned 1903–1914) or Pope Paul VI (reigned 1963–1978).
Ceremonial in the past
A papal Mass celebrated in the early 20th century, before the liturgical reforms of Popes Pius X and Paul VI, took this form:
Assistant ministers
In the papal Mass a cardinal-bishop acted as assistant priest; this honor fell on the most solemn occasions to the Cardinal-bishop of Ostia, the Dean of the College of Cardinals. Cardinal-deacons acted as deacon and assistant deacons. An auditor of the Sacra Rota served as subdeacon. There were also a Greek-Catholic deacon and subdeacon, vested according to the Byzantine Rite. The other offices were filled by the assistants to the pontifical throne, the members of the prelatical colleges, etc.
Those acting as deacon and subdeacon were at times referred to as apostolic deacon and apostolic subdeacon.
Vestments
Before the beginning of the ceremony, the pope was vested in the falda (a particular papal vestment which forms a long skirt extending beneath the hem of the alb), amice, alb, cincture, pectoral cross, stole, and a very long cope known as the "mantum" (or "papal mantle"). Finally, the papal tiara was placed on his head.
Entrance
The pope's solemn entry into St. Peter's Basilica was accompanied by the Silveri Symphony, a fanfare played on the trumpets of the Noble Guard. The entrance procession was headed by the cardinals, bishops, prelates, and those who composed the pontifical capella, vested according to their rank and in their prescribed order of precedence. A thurifer and seven acolytes accompanied the crucifer, and the apostolic subdeacon carried the Gospel Book (a function now reserved to a deacon). At the end of the procession the pope was carried into the basilica on the sedia gestatoria and with the two flabella borne on either side. He was accompanied by an entourage which included the Swiss Guards in their colorful uniforms and members of the Roman nobility in formal court dress. At times, a canopy was carried above his head. Two protonotaries apostolic raised the front of the falda as the pope walked to and from the sedia, and two papal chamberlains carried the train. The dean of the Rota carried the jewelled mitre (the mitra pretiosa), and finally two patriarchs or archbishops carried the book and bugia (hand-candle) respectively.
The pope was received at the door by the cardinal-priest and the Canons of St. Peter's. He then knelt briefly, leaning on a faldstool, to adore the Blessed Sacrament. Fittingly, this often took place at the St. Gregory's Altar in St. Peter's. He then went to the small throne for the chanting of Terce, during which he received the obedience of the cardinals, bishops, and abbots. While the psalms of Terce were being chanted, he read the prayers of preparation for Mass, during which his buskins and papal slippers were put on. He then sang the prayer of Terce.
After Terce, his outer vestments were removed, leaving only the falda, amice, alb, and cincture. The pope washed his hands, and put on the following vestments (in order), assisted by the deacon: sub-cinctorium pectoral cross fanon (lower & upper piece) — a two piece vestment worn only by the pope during Solemn High Mass, with the two pieces connected only by a central buttonhole. It resembled a shoulder cape with alternating stripes of silver and gold. stole tunicle dalmatic episcopal gloves chasuble fanon (upper piece only) — The upper piece was pulled out from under the other vestments, and was worn over the chasuble and under the pallium. The lower piece remained under the other vestments. pallium mitre episcopal ring (He did not use the crosier or the bugia at this point.) He then gave the kiss of peace to the last three of the cardinal-priests.
The Mass
The Mass proceeded according to the order of a solemn pontifical high Mass with the following differences: