Peter Paul Rubens, “Saint Peter as Pope”, ca. 1611
“The Roman Pontiff, head of the college of bishops, enjoys this infallibility in virtue of his office...” (LG 25)
Historically, there were many expressions similar to “papal infallibility”, such as: papal authority, papal primacy, headship, papal supremacy, Roman primacy, etc. All of those can be traced back to very early times. Papal infallibility developed (i.e., became more fully understood in its detail) just as all Christian doctrines do.
But if we restrict ourselves to uses of the word infallibility itself, (and with direct reference to the pope), one notable historical use comes from a Doctor of the Church, St. Francis de Sales, and his book, The Catholic Controversy, completed in 1596. Note how remarkably it anticipates the later fully developed dogma of papal infallibility, as pronounced at the First Vatican Council in 1870 (274 years before it):
When he teaches the whole Church as shepherd, in general matters of faith and morals, then there is nothing but doctrine and truth. And in fact everything a king says is not a law or an edict, but that only which a king says as king and as a legislator. So everything the Pope says is not canon law or of legal obligation; he must mean to define and to lay down the law for the sheep, and he must keep the due order and form.
We must not think that in everything and everywhere his judgment is infallible, but then only when he gives judgment on a matter of faith in questions necessary to the whole Church; for in particular cases which depend on human fact he can err, there is no doubt, though it is not for us to control him in these cases save with all reverence, submission, and discretion. Theologians have said, in a word, that he can err in questions of fact, not in questions of right; that he can err extra cathedram, outside the chair of Peter. that is, as a private individual, by writings and bad example.
But he cannot err when he is in cathedra, that is, when he intends to make an instruction and decree for the guidance of the whole Church, when he means to confirm his brethren as supreme pastor, and to conduct them into the pastures of the faith. For then it is not so much man who determines, resolves, and defines as it is the Blessed Holy Spirit by man, which Spirit, according to the promise made by Our Lord to the Apostles, teaches all truth to the Church. (The Catholic Controversy, translated by Henry B. Mackey, Rockford, Illinois: TAN Books, 1989, 306-307)
Yet critics of the Catholic Church often erroneously contend that no one claimed that the pope was infallible until the 19th century.
Another example dates from a 1690 Decree of the Holy Office during the reign of Pope Alexander VIII (1689-1691): Errors of the Jansenists. Among the errors condemned is the following:
29. The assertion of the authority of the Roman Pontiff over an ecumenical council and infallibility in deciding questions of faith is futile and often contradicted. (Heinrich Denzinger, Compendium of Creeds. . .[Enchiridion Symbolorum], San Francisco: Ignatius Press, 2012, 43rd edition #2329)
This is decried as “Condemned and prohibited” as “rash, scandalous, evil-sounding, unjust, proximate to heresy, having the flavor of heresy, erroneous, schismatic, and heretical.”
We also have a relevant magisterial statement from 350 years before 1870: the condemnation of Martin Luther’s errors in the papal Bull Exsurge Domine, of June 15, 1520. Here are two of the 41 propositions roundly condemned:
[Denzinger number] #1477 (#27). It is certain that it is not in the power of the Church or the pope to decide upon the articles of faith, and much less concerning the laws for morals or for good works.
#1478 (#28). If the pope with a great part of the Church thought so and so, he would not err; still it is not a sin or heresy to think the contrary, especially in a matter not necessary for salvation, until one alternative is condemned and another approved by a universal council.
As is often said in discussions on the history of development of Christian doctrine (citing Cardinal Newman): “a doctrine is not defined until it is violated.”
Martin Luther hadn’t expressly denied papal authority per se in his 95 Theses (Oct. 31, 1517). But he did by the time of the 18-day Leipzig Disputation with John Eck in July 1519, when he was essentially pressed into adopting something akin to sola Scriptura, and rejecting papal and conciliar infallibility.
Luther biographer Roland Bainton notes how Luther by 1518 “had further declared the pope and councils to be capable of error.” (Here I Stand, New York: Mentor, 1950, 78-79). He recounts the dramatic climax of the Leipzig Disputation:
“Let me talk German,” demanded Luther. “I am being misunderstood by the people. I assert that a council has sometimes erred and may sometimes err. . . . Councils have contradicted each other, for the recent Lateran Council has reversed the claim of the councils of Constance and Basel that a council is above a pope. A simple layman armed with Scripture is to be believed above a pope or a council without it. As for the pope’s decretal on indulgences I say that neither the Church nor the pope can establish articles of faith. These must come from Scripture. For the sake of Scripture we should reject pope and councils.”
“But this,” said Eck, “is the Bohemian virus, to attach more weight to one’s own interpretation of Scripture than to that of the popes and councils, the doctors and the universities. . . . They have all appealed to Scripture and have believed their interpretation to be correct, and have claimed that the popes and the councils were mistaken, as Luther now does. It is rancid to say that those gathered in a council, being men, are able to err. (Ibid., 90)
Thus, the Leipzig Disputation in 1519 is additional evidence of existing Catholic traditions of papal and conciliar infallibility: that Luther was rejecting.