The term ‘ordinary magisterium’ was first used by Pius IX in the letter Tuas libenter addressed to the archbishop of Munich and Freising on 21 December 1863.
Earlier that year, a meeting of Catholic theologians had taken place in Munich. The pope had been told that in the course of that meeting the opinion had been expressed that Catholic theologians were bound to hold only those truths of faith which had been solemnly declared.
Pius IX replied that “it must not be limited to those things which have been defined by the express decrees of councils or of the Roman Pontiffs and of this Apostolic See, but must also be extended to those things which are handed on by the ordinary magisterium of the whole church dispersed throughout the world as divinely revealed, and therefore are held by the universal and constant consensus of Catholic theologians to pertain to the faith.”
Tuas libenterExcerpts (they seem to be excerpts rather than the whole letter) from a letter issued by Bl. Pius IX (from the book Papal Teachings: The Church put together by the Benedictine monks of Solesmes):
OBEDIENCE TO THE TEACHING POWER
Letter Tuas libenter, December 21, 1863, to the Archbishop Munich.
(The theological and philosophical Congress at Munich.—Laudable intentions of its organizers.)
It was impossible for Us not to be extremely surprised to see that the convocation of the aforesaid Congress was issued and published in the name of certain private individuals, such that nothing appeared which came from the impulsion, the authority, and the missions of the ecclesiastical power, to which alone it belongs by a proper and natural right to supervise and direct teaching, particularly in matters which relate to theological teaching, particularly in matters which relate to theological questions. Certainly, as you know, this is a state of affairs entirely new and contrary to the custom of the Church. This is why, Venerable Brother, We wished to communicate Our thoughts to you, so that you and your Venerable Brothers, the Bishops of Germany, will be in a position to judge accurately whether the end proposed by the Congress is of a nature to be useful to the Church. At the same time, We were certain, Venerable Brother, that in your pastoral solicitude, you would employ all the wisdom and efforts of your zeal to prevent, during this Congress, any harm resulting either to the integrity of the faith and Catholic teaching, or to the entire obedience which Catholics of every rank and condition owe to the authority of the Church and to the teaching mission which she has received.
For the rest, We cannot hide from you that We have been made rather anxious: for We feared that the example of this Congress, assembled independently of the ecclesiastical authority, might little by little do damage to the right of spiritual government and legitimate teaching which, in virtue of the divine institution, belongs properly to the Roman Pontiff and to the bishops who in union and agreement with the Successor of St. Peter; and that, as a consequence of this harm done to the government of the Church, the principle of unity and obedience in matters of faith might eventually be weakened in many souls. We feared also lest, in the same Congress, opinions and systems might be aired and supported which, by reason above all of the publicity given to them, would imperil the purity of doctrine and the duty of obedience.
(Recent errors of German writers on the subject of revealed faith.)
Science and the teaching authority
We knew also, Venerable Brother, that among the Catholics devoted to the study of the higher sciences, there are some who, counting too much on the powers of the human mind, have not allowed themselves to be checked by the fear of lapsing into error, and who, desirous of a deceptive and hardly sincere liberty for science, have been drawn beyond the limits which cannot be exceeded without renouncing the obedience due to the divine authority which the Church has received to teach and preserve intact the entire deposit of revealed truth. Whence it happens that these Catholics, dupes of unfortunate illusions, are often to be found in agreement with those who rant against the decrees of this Apostolic See and of Our Congregations, saying that these decrees are an obstacle to the progress of science, and they are thus exposed to the rupture of those sacred bonds of obedience which, in order of the Divine Will, ought to attach them to this same Apostolic See, instituted by God Himself as the interpreter and defender of truth.
We are not ignorant either that in Germany false prejudices have prevailed against the ancient school and against the teaching of the great Doctors whom the universal Church reveres for their admirable wisdom and the sanctity of their lives. This false estimate which has been made impugns the very authority of the Church itself, since it is the Church who, for so many centuries on end, not only has permitted theological science to be cultivated according to the method of these Doctors and according to the principles made sacred by the unanimous agreement of the Catholic Schools, but has moreover often given the highest praise to their theological learning and has strongly recommended it as offering the best means of defending the faith and of supplying the most effective arms against her enemies.
(Usefulness of the Congess.—Science and revelation, reason and faith.)
The extent of obedience
We address to the members of this Congress well-merited praise, because, rejecting, as We expected they would, this false distinction between the philosopher and the philosophy of which We have spoken in earlier letters, they have recognized and accepted that all Catholics are obliged in conscience in their writings to obey the dogmatic decrees of the Catholic Church, which is infallible. In giving them the paraise which is their due for confessing a truth which flows necessarily from the obligation of the Catholic faith, We love to think that they have not intended to restrict this obligation of obedience, which is strictly binding on Catholic professors and writers, solely to the points defined by the infallible judgment of the Church as dogmas of faith which all men must believe. And We are persuaded that they have not intended to declare that this perfect adhesion to revealed truths, which they have recognized to be absolutely necessary to the true progress of science and the refutation of error, could be theirs if faith and obedience were only accorded to dogmas expressly defined by the Church. Even when it is only a question of the submission owed to divine faith, this cannot be limited merely to points defined by the express decrees of the Ecumenical Councils, or of the Roman Pontiffs and of this Apostolic See; this submission must also be extended to all that has been handed down as divinely revealed by the ordinary teaching authority of the entire Church spread over the whole world, and which, for this reason, Catholic theologians, with a universal and constant consent, regard as being of the faith. But, since it is a question of the submission obliging in conscience all those Catholic who are engaged in that study of the speculative sciences so as to procure for the Church new advantages by their writings, the members of the Congress must recognize that it is not sufficient for Catholic savants to accept and respect the dogmas of the Church which We have been speaking about: they must, besides, submit themselves, whether to doctrinal decisions stemming from pontifical congregations, or to points of doctrine which, with common and constant consent, are held in the Church as truths and as theological conclusions so certain that opposing opinions, though they may not be dubbed heretical, nonetheless, merit some other form of theological censure.
(Hope that the members of the Congress will admit all these points.—Their protestations of fidelity to the Holy See.)
Since these are the sentiments with which they recognize Our supreme authority and the power of the Apostolic See, since at the same time, they understand the gravity of the office which Our Lord Jesus Christ Himself has imposed upon Us to govern and direct the entire Church, to lead his flock into pastures of healthful doctrine and to watch incessantly that holy faith and his teaching receive not the slightest alteration. We cannot doubt but that in devoting themselves to the study and teaching of the higher sciences and the defense of sound doctrine, they will recognize also their duty to follow most religiously the rules constantly observed in the Church, and to obey all the decrees handed down in doctrinal matters by Our supreme pontifical authority.