A Papal Mass is the Solemn Pontifical High Mass when offered by the Pope of the Roman Catholic Church.

There are numerous special ceremonials which are particular to the pope. A Solemn Papal Mass would be celebrated on solemn occasions such as a Papal Coronation, an ex cathedra pronouncement, the canonization of a saint, or a major feast such as Easter or Christmas.

Many of the ceremonies that were once connected with such a Mass have fallen out of use since the time of Pope Paul VI and some, such as the reservation of Communion to the Pope, the deacon and the subdeacon, since the time of Pope Pius X.

What follows is a description of usage in the early twentieth century, before the liturgical reforms of Pope Paul VI.

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 were assistant deacons and deacon of the Mass, 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.

The Venerable Pope Pius XII (Latin: Pius PP. XII; Italian: Pio XII), born Eugenio Marìa Giuseppe Giovanni Pacelli (2 March 1876 – 9 October 1958), reigned as Pope, head of the Catholic Church and sovereign of Vatican City State, from 2 March 1939 until his death in 1958.

Before election to the papacy, Pacelli served as secretary of the Department of Extraordinary Ecclesiastical Affairs, papal nuncio and Cardinal Secretary of State, in which capacity he worked to conclude treaties with European and Latin American nations, most notably the Reichskonkordat with Nazi Germany. The concordat of 1933 which saw the self-destruction of the Centre (Catholic) Party, on the orders of the Holy See, and Pius' leadership of the Catholic Church during World War II, including his "decision to stay silent in public about the fate of the Jews", remain the subject of controversy.

After the war Pius XII advocated peace and reconciliation, including lenient policies towards Axis and Axis-satellite nations. The Church experienced severe persecution and mass deportations of Catholic clergy in the Eastern Bloc. In light of his overt involvement in Italian politics – anyone who voted for a Communist candidate in the 1948 elections was threatened with automatic excommunication – Pius XII became known as a staunch opponent of the Italian Communist Party. Pius XII explicitly invoked ex cathedra papal infallibility with the dogma of the Assumption of Mary in his 1950 Apostolic constitution Munificentissimus Deus. His magisterium includes almost 1,000 addresses and radio broadcasts. His forty-one encyclicals include Mystici Corporis, the Church as the Body of Christ; Mediator Dei on liturgy reform; and Humani generis on the Church's positions on theology and evolution. He eliminated the Italian majority in the College of Cardinals in 1946.

Benedict XVI (Latin: Benedictus PP. XVI; Italian: Benedetto XVI; German: Benedikt XVI.; born Joseph Aloisius Ratzinger on 16 April 1927) is the 265th Pope, a position in which he serves dual roles as Sovereign of the Vatican City State and leader of the Catholic Church. As pope he is regarded as the successor of Saint Peter. Benedict XVI was elected on 19 April 2005 in a papal conclave, celebrated his Papal Inauguration Mass on 24 April 2005, and took possession of his cathedral, the Archbasilica of St. John Lateran, on 7 May 2005. A native of Bavaria, Pope Benedict XVI has both German and Vatican citizenship.

After a long career as an academic, serving as a professor of theology at various German universities—the last being the University of Regensburg—he was appointed Archbishop of Munich and Freising and cardinal by Pope Paul VI in 1977. In 1981, he settled in Rome when he became Prefect of the Congregation for the Doctrine of the Faith, one of the most important dicasteries of the Roman Curia. From 2002 until his election as Pope, he was also Dean of the College of Cardinals, and as such the primus inter pares among the cardinals. Prior to becoming Pope, he was "a major figure on the Vatican stage for a quarter of a century" as "one of the most respected, influential and controversial members of the College of Cardinals"; he had an influence "second to none when it came to setting church priorities and directions" as one of Pope John Paul II's closest confidants.