Defined the primacy and the infallibility of the pope, in carefully limited terms — then broke off when Italian troops took Rome.
- Where
- St. Peter's Basilica, Rome — Vatican City
- Convoked by
- Pope Pius IX, by the bull Aeterni Patris of 29 June 1868
- Pope
- Pius IX, the longest-reigning pope in history
- Sat
- Opened 8 December 1869; suspended 20 October 1870; formally closed only in 1960, by John XXIII
- Sessions
- Four public sessions in the north transept of St. Peter's, fitted out as a council hall
- Bishops present
- Some 700 fathers at the opening — the first council with a genuinely worldwide episcopate, including bishops from the Americas, Asia, Africa and Australia
What it faced
The nineteenth century had taken almost everything from the papacy except the argument. The Papal States were being swallowed by Italian unification; rationalism denied that revelation was possible; and inside the Church, Gallicanism in France and Febronianism in Germany held that a pope's judgments bind only when the bishops of the world consent to them.
That last question was the practical one. If a papal definition needs subsequent ratification by the episcopate to be binding, then in any real crisis there is no way to settle anything, because the ratification is exactly what will be disputed.
The council was fiercely divided, not over whether the pope teaches infallibly but over whether saying so was opportune. The minority — Newman among the sympathisers, though he was not at the council — feared that a definition would be read maximally, would harden Protestant and Orthodox opposition, and would make every papal utterance sound like a dogma.
What it defined
- ✠In Dei Filius: that God can be known with certainty by the natural light of human reason from created things; and that faith and reason, both from God, can never truly contradict each other.
- ✠In Pastor Aeternus: that the Roman pontiff holds a primacy of ordinary, immediate and truly episcopal jurisdiction over the whole Church.
- ✠That when the pope speaks ex cathedra — as pastor and teacher of all Christians, by his supreme apostolic authority, defining a doctrine of faith or morals to be held by the whole Church — he possesses the infallibility Christ willed his Church to have.
- ✠That such definitions are irreformable of themselves, and not by the consent of the Church.
In its own words
“…we teach and define as a divinely revealed dogma that when the Roman pontiff speaks EX CATHEDRA, that is, when, in the exercise of his office as shepherd and teacher of all Christians, in virtue of his supreme apostolic authority, he defines a doctrine concerning faith or morals to be held by the whole church, he possesses, by the divine assistance promised to him in blessed Peter, that infallibility which the divine Redeemer willed his church to enjoy in defining doctrine concerning faith or morals. Therefore, such definitions of the Roman pontiff are of themselves, and not by the consent of the church, irreformable.”
“God… can be known with certainty from the consideration of created things, by the natural power of human reason.”
Its constitutions
Two dogmatic constitutions. The council was suspended before it could take up anything else.
- Dei FiliusOn God the creator, revelation, faith, and the relation of faith to reason — with canons against pantheism, materialism, rationalism and fideism.
- Pastor Aeternus, ch. 1–3The primacy of Peter, its perpetuity in the Roman pontiffs, and the nature and force of that primacy as ordinary and immediate jurisdiction.
- Pastor Aeternus, ch. 4The infallible teaching authority of the Roman pontiff, with its four conditions.
- ✕It did not teach that the pope is impeccable, or that everything he says is infallible. The definition sets four conditions at once: he must speak as universal pastor, by his supreme authority, defining a doctrine of faith or morals, for the whole Church. Ordinary teaching, private opinions, interviews, letters and political judgments fall outside it.
- ✕It did not make the pope a substitute for the bishops. The council was suspended before it could take up the chapters on the episcopate, which is exactly why Vatican II's teaching on collegiality in Lumen Gentium was described by Paul VI as completing a council left half-finished.
- ✕It did not intend the definition to be read maximally. Bishop Gasser's official relatio to the council explained the text in deliberately restrictive terms, and it is the interpretive key the Church has used ever since.
- ✕It did not finish. Italian troops entered Rome through the Porta Pia on 20 September 1870; the council was suspended on 20 October and never reconvened.
What people think it did
Since 1870 Catholics have had to believe whatever the pope says.
What happened: The definition is one of the most tightly drawn in the history of doctrine, precisely because the fathers feared this reading. Four conditions must all hold, and they exclude the vast bulk of what any pope says. The Church distinguishes carefully between what is defined, what is definitively held, and what is authoritative but not definitive — a distinction the doctrines section of this site sets out in full.
The council invented papal infallibility in 1870.
What happened: It defined it in 1870; the claim it defined is older. The Council of Florence in 1439 had already declared the Roman pontiff 'true vicar of Christ, head of the whole Church', with full power to rule and govern it. What was genuinely new was the precision — and the negative half, the ruling that such definitions do not require the consent of the Church to be binding, which was aimed squarely at Gallicanism.
What followed
The vote on 18 July 1870 was overwhelming, and the accounts of it differ in a way worth reporting rather than smoothing: the Catholic Encyclopedia gives 433 placet and 2 non placet out of 435 present, while other reckonings give 533 to 2. What is not disputed is that about sixty bishops of the minority left Rome the day before rather than vote against the pope in public — and that both of the two who did vote against, the bishop of Cajazzo and Edward Fitzgerald of Little Rock, submitted immediately.
The dogma has been invoked, by the common reckoning, exactly once since: by Pius XII in 1950, defining the Assumption. The Immaculate Conception of 1854 was defined before the council and is generally counted as the other instance. Two definitions in a hundred and seventy years is not what the council's critics predicted.
The war and the fall of Rome did what no theological argument could: the pope lost his last territory the same summer he gained a defined authority, and the papacy's moral influence has grown ever since almost in proportion to its loss of temporal power.
Follow it further
Sources
Every date, figure and quotation on this page was checked against the conciliar text or a published translation before it was written, and independently re-checked by three separate passes over dates, quotations and theology. Where the sources disagree — attendance figures above all — the page gives the range rather than choosing.