Sedevacantism is a traditionalist Catholic movement which holds that since the death of Pius XII the alleged occupiers of the Holy See are not valid popes due to their espousal of one or more heresies and that, for lack of a valid pope, the See of Rome is thus vacant. Sedevacantism owes its origins to the rejection of the theological and disciplinary changes implemented following the Second Vatican Council (1962–1965).
Marcel François Marie Joseph Lefebvre was a French Catholic archbishop who influenced modern traditional Catholicism. In 1970, five years after the close of the Second Vatican Council, he founded the Society of Saint Pius X (SSPX), a community to train seminarians in the traditional manner, in the village of Écône, Switzerland. In 1988, Pope John Paul II declared that Archbishop Lefebvre had "incurred the grave penalty of excommunication envisaged by ecclesiastical law" for consecrating four bishops against the pope's express prohibition but, according to Lefebvre, in reliance on an "agreement given by the Holy See [...] for the consecration of one bishop."
Pierre Martin Ngô Đình Thục was the Roman Catholic Archbishop of Huế, Vietnam, and later a sedevacantist bishop who was excommunicated by the Holy See but is thought to have reconciled with the Holy See before his death in 1984. He was a member of the Ngô family who ruled South Vietnam in the years leading up to the Vietnam War. He was the founder of Dalat University. Today, various Independent Catholic and sedevacantist groups claim to have derived their apostolic succession from Thục.
Traditionalist Catholicism is a movement encompassing members of the Catholic Church and offshoot groups of the Catholic Church that emphasizes beliefs, practices, customs, traditions, liturgical forms, devotions and presentations of teaching associated with the Catholic Church before the Second Vatican Council (1962–65). Traditionalist Catholics particularly emphasize the Tridentine Mass, the Roman Rite liturgy largely replaced in general use by the post-Second Vatican Council Mass of Paul VI.
Daniel Lytle Dolan was an American sedevacantist bishop.
The Society of Saint Pius X, also known as the Lefebvrists, is a canonically irregular international fraternity of traditionalist Catholic priests founded in 1970 by Archbishop Marcel Lefebvre, a leading traditionalist voice at the Second Vatican Council with the Coetus Internationalis Patrum and Superior General of the Holy Ghost Fathers until 1968. The society was initially established as a pious union of the Catholic Church with the permission of François Charrière, the Bishop of Lausanne, Geneva and Fribourg in Switzerland. In 2022, the society reached over 700 priestly members, with 1,135 total members.
The Society of Saint Pius V is a traditionalist Catholic society of priests, formed in 1983, and based in Oyster Bay Cove, New York, United States. The society broke away from the Society of Saint Pius X (SSPX) over liturgical issues.
Ecclesia Dei is the document Pope John Paul II issued on 2 July 1988 in reaction to the Ecône consecrations, in which four priests of the Society of Saint Pius X were ordained as bishops despite an express prohibition by the Holy See. The consecrating bishop and the four priests consecrated were excommunicated. John Paul called for unity and established the Pontifical Commission Ecclesia Dei to foster a dialogue with those associated with the consecrations who hoped to maintain both loyalty to the papacy and their attachment to traditional liturgical forms.
Bernard Fellay is a Swiss bishop and former superior general of the Traditionalist Catholic priestly fraternity Society of Saint Pius X (SSPX). In 1988, Pope John Paul II announced that Fellay and three others were automatically excommunicated for being consecrated as bishops by Archbishop Marcel Lefebvre, an act that the Holy See described as "unlawful" and "schismatic". Archbishop Lefebvre, and Bishop Antônio de Castro Mayer who co-consecrated these four bishops, were also said to be automatically excommunicated. At that time, he was the youngest bishop of the Roman Catholic Church at 30 years old.
Bernard Tissier de Mallerais is a French traditionalist Catholic prelate, serving as a bishop of the Society of Saint Pius X.
Alfonso de Galarreta Genua,, is a Spanish-born Argentine bishop of the Society of Saint Pius X. Bishop de Galarreta has served as the First Assistant of the Society of Saint Pius X, working under the direction of the Superior General Fr. Davide Pagliarani, since 2018. In addition to this, Bishop de Galaretta has been the President of the SSPX—Vatican Commission since 2009, which directs the Society's correspondence with the Holy See.
The International Seminary of Saint Pius X in Écône, Valais, Switzerland is the premier seminary of the Roman Catholic traditionalist Society of Saint Pius X (SSPX). The seminary is one of the six houses for formation for the future priests of the Society of Saint Pius X. The Seminary was founded in 1970 by Archbishop Marcel Lefebvre, and his tomb can be found there.
Antônio de Castro Mayer was a Brazilian prelate of the Roman Catholic Church. A Traditionalist Catholic and ally of Archbishop Marcel Lefebvre, he was Bishop of Campos from 1949 until his resignation in 1981.
Clarence Kelly was an American sedevacantist traditionalist Catholic bishop. He was a co-founder of the Society of Saint Pius V and the founder of the Congregation of Saint Pius V.
Anthony J. Cekada was an American sedevacantist Catholic priest and author.
Michel-Louis Guérard des Lauriers was a French Dominican theologian and, later in life, a Traditionalist Catholic bishop who supported sedevacantism and sedeprivationism and was excommunicated by the Holy See.
The Écône consecrations were Catholic episcopal consecrations in Écône, Switzerland, on 30 June 1988 performed by Archbishop Marcel Lefebvre and Bishop Antônio de Castro Mayer. The bishops consecrated were four priests of Lefebvre's Society of Saint Pius X (SSPX). The consecrations, performed against the explicit orders of Pope John Paul II, represented a milestone in the troubled relationship of Lefebvre and the SSPX with the Church leadership. The Holy See's Congregation for Bishops issued a decree signed by its Prefect Cardinal Bernardin Gantin declaring that Lefebvre and De Castro Mayer had incurred automatic excommunication by consecrating the bishops without papal consent, thus putting himself and his followers in schism.
The canonical situation of the Society of Saint Pius X (SSPX), a group founded in 1970 by Archbishop Marcel Lefebvre, is unresolved.
Paul William Morgan is the former superior of the British district of the Society of St Pius X, a traditionalist Catholic organisation in irregular canonical standing with the Holy See.
Alfredo José Isaac Cecilio Francesco Méndez-Gonzalez was an American Catholic bishop who served in Puerto Rico and who later became involved with sedevacantists.
