In 1854, Pius IX decreed the doctrine of the Immaculate Conception to be infallible in his bull, Ineffabilis Deus. The First Vatican Council in 1869-70, in its Pastor Aeternus decree, declared that the pope was infallible when he spoke “ex Cathedra” – or from the papal throne – on matters of faith and morals.

When was papal infallibility established?

Vatican Council I in 1870 declared that any such ex cathedra doctrines have the character of infaillibility (session 4, Constitution on the Church 4)." The solemn declaration of papal infallibility by Vatican I took place on 18 July 1870.

Why was papal infallibility created?

The idea of papal infallibility arises in the thirteenth century in the context of increasing Franciscan influence at the papal curia. Pope Nicholas III (1277-1280) had approved the idea of apostolic poverty and arranged for the papacy to own all the Franciscans' wealth to allow them to live in poverty.