The First Vatican Council: the dogma of papal infallibility

Pius IX's bull Ineffabilis Deus (1854) was, for the first time in the history of the Church, a dogmatic definition made by the pope alone, and it convinced the ultramontanes that the proclamation of papal infallibility was near. At the First Vatican Council, convened in 1868, some wanted a definition without limits, the majority a definition that took into account popes who had fallen into heresy (Liberius, Honorius), some bishops considered the moment inopportune, and a minority led by the archbishops of Vienna and Prague rejected the teaching. In July 1870 the constitution "The Church of Christ" proclaimed that the Roman pontiff, speaking ex cathedra, possesses the infallibility with which the Redeemer willed His Church to be endowed, and that his definitions are "irreformable of themselves and not from the consent of the church." The same decree affirmed the pope's direct jurisdiction over the whole Church.