I am posting the following from the standpoint that “there is no such thing as a ‘stupid question’.” I think I know the answer, but I freely and openly admit that could be wrong.
I am under the impression that there are only two infallible doctrines, where the Pope spoke from the “chair of Peter”, throughout the entire history of the Catholic Church.
These are the Immaculate Conception of Mary and the Assumption of Mary into Heaven. Two times in nearly 2,000 years. Am I wrong about this? Am I missing something?
Here is a list of all of the ex cathedra pronouncements
outside of Councils that I copied from somewhere some years ago.
In a book published in 1954 by Fathers Leslie Rumble & Charles Carty (of the Radio Replies series, the best-known Roman Catholic apologists of the 1940s and 1950s), That Catholic Church: A Radio Analysis gave the following list (reformatted for readability but otherwise unchanged) of papal statements regarded as ex cathedra (on Question/Answer #314 on page 80):
Leo I, Lectis Dilectionis Tuae, 13 June 449,
On the divinity of Christ.
Agatho, Omnium Bonorum Spes, ~680,
On the divine and human wills in Christ.
Boniface VII, Unam Sanctam, 18 Nov 1302,
On papal supremacy in the Church.
Benedict XII, Benedictus Deus, 29 Jan 1336,
On the heavenly destiny of saints.
Leo X, Exsurge Domine, 15 June 1520,
Condemning the errors of Martin Luther.
Innocent X, Cum Occasione, 31 May 1653,
Condemning the errors of the Jansenists.
Innocent XI, Coelestis Pastor, 19 Nov 1687,
Condemning the erros of the Quietists.
Clement XI, Unigenitus, 8 Sept 1713,
Condemning the false teachings of Paschasius Quesnel.
Pius VI, Auctorem Fidei, 28 Aug 1794,
Condemning the false teachings of the Synod of Pistoia.
Pius IX, Ineffabilis Deus, 8 Dec 1854,
Defining the dogma of the Immaculate Conception.
also, Quantae Cura, 8 Dec 1864,
Condemning the erros of secularism and communism.
Leo XIII, Apostolicae Curae, 13 Sept 1896,
Condemning Anglican orders as null and void.
also, Testem Benevolentiae, 22 Jan 1899,
Condemning merely Naturalistic interpretations of Christian Activities.
[A few theologians say these two are not technically ex cathedra.]
Pius X, Lamentabili, 3 July 1907, also, Pascendi, 7 Sept, 1907,
Condeming the errors of the Modernists.
Pius XI, Casti Connubii, 31 Dec 1930,
Calling contraceptive birth control a grave violation of the Law of God.
Quadragesimo Anno, 15 May 1931,
Condeming materialistic socialism.
[These two are “very probably” comply with ex cathedra requirements]
Pius XII, Munificentissimus Deus, 1 Nov 1950,
Defining the dogma of the Assumption.