Sedevacantism owes its origins to the rejection of the theological and disciplinary changes implemented following the Second Vatican Council (1962–65). Sedevacantists reject this Council, on the basis of their interpretation of its documents on ecumenism and religious liberty, among others, which they see as contradicting the traditional teachings of the Catholic Church and as denying the unique mission of Catholicism as the one true religion, outside of which there is no salvation. They also say that new disciplinary norms, such as the Mass of Paul VI, promulgated on 3 April 1969, undermine or conflict with the historical Catholic faith and are deemed blasphemous, while post-Vatican II teachings, particularly those related to ecumenism, are labelled heresies. They conclude, on the basis of their rejection of the revised Mass rite and of postconciliar Church teaching as false, that the popes involved are false also.