Sedevacantism

Sedevacantism is the term commonly used to denote the belief, held by a minority of Traditionalist Catholics, that some or all of the men generally recognized as Popes since the death of Pope Pius XII in 1958 (Pope John XXIII, Pope Paul VI, Pope John Paul I, Pope John Paul II and Pope Benedict XVI) have not truly held the papal office, and have hence been antipopes. The word is derived from the Latin phrase "sede vacante", which means "while the See is vacant" and is used in Vatican documents in the interval between the death or abdication of the Pope and the election of his successor.

Main sedevacanist groups

• Society of St. Pius V (formed when a small number of priests of the Society of St. Pius X split from that organisation over the issue of sedevacantism)
• The Ngô Ðình Thuc Pierre Martin line of episcopal succession
• Congregation of Mary Immaculate Queen