Supreme apostolic authority, he lays down that a certain doctrine concerning faith or morals is binding, upon the universal Church, - possesses, by the Divine assistance which was promised to him in the person of the blessed Saint Peter, that same infallibility with which the Divine Redeemer thought fit to endow His Church, to define its doctrine with regard to faith and morals; and, consequently, that these definitions of the Roman Pontiff are irreformable in themselves, and not in consequence.
The only reservation which the most advanced Gallicans dared to formulate, in the terms of the celebrated declaration of the clergy of France (1682), had as its object the irreformable character of the pontifical definitions, which, it was claimed, could only have been acquired by them through the assent of the Church.
(2) In the matter of infallibility: "We decree that when the Roman Pontiff speaks ex cathedra, that is to say, when, in his capacity as Pastor and Doctor of all Christians he defines, in virtue of his supreme apostolic authority, a certain doctrine concerning faith or morals to be held by the whole Church, he enjoys, by the divine assistance promised to him in the Blessed Peter, that infallibility with which the divine Redeemer has thought good to endow His Church in order to define its doctrine in matters of faith and morals; consequently, these definitions of the Roman Pontiff are irreformable in themselves and not in consequence of the consent of the Church."
On the 18th of July the pope's decrees were declared " irreformable of themselves, irrespectively of the consent of the Church," always provided that they dealt with doctrines of faith and morals, and were delivered ex cathedra - that is, with the intention of binding the consciences of all Catholics.
The second and decisive victory followed at the Vatican Council (1870), which, at the cost of a small secession of distinguished men, declared the pope personally infallible (see Infallibility) and irreformable as often as he rules ex cathedra points of faith or morals.