Today, the 18th of July, is reserved for some saints; particularly Symphorosa and her seven sons, who were tortured and killed on the same day by emperor Adrian for refusing to give up their Christian beliefs.
This day also is the day that Pius IX, in the year 1870, at the Ecumenical Council of the Vatican, defined, in its constitution,
Pastor AEternus, the full, supreme, and immediate power of the Roman Pontiff over all the Churches, and pronounced anathema against
all who should refuse to recognize the personal infallibility of the same Roman Pontiff, speaking
ex cathedra--i.e., defining, as universal pastor, any doctrine concerning Faith or morals. This only is in effect when those proclamations are passing on what the Church has always taught, not like some of the nonsense being taught today, which is more like 'protestantism', and which the Church has
NOT always taught. Following is that constitution:
First Vatican Council
Dogmatic Constitution ‘Pastor Aeternus’, Chapter 4
18 July 1870
On the Infallibility of the Roman Pontiff
First Vatican Council
§ 1. In the apostolic primacy which the Roman Pontiff holds in the universal Church as successor of Peter, the Prince of the Apostles, there is also included the supreme power of teaching. This Holy See has always held this [truth], the perpetual practice of the Church approves it, and the ecumenical Councils, especially those in which the East has come together with the West in a union of faith and charity, have taught it.
§ 2. For the bishops of the Fourth Council of Constantinople, adhering to the footsteps of their predecessors, issued this solemn profession: "The first thing required for salvation is to preserve the rule of the true faith. And because it is not possible to set aside the words of Our Lord Jesus Christ when he says, 'You are Peter, and upon this rock I will build my Church,' we see that these words are proved true by events, because the Catholic faith has always been preserved immaculate in the Apostolic See and its teaching kept holy. Therefore, desiring to be separated in no way from this faith and teaching, we hope that we may deserve to be in the one communion which the Apostolic See preaches, in which [See] there is present the whole and true security of the Christian religion."
§ 3. Indeed, with the approval of the Second Council of Lyons, the Greeks professed: "The Holy Roman Church holds the supreme and full primacy and power over the universal Catholic Church. She humbly and truly recognizes that she has received this from the Lord Himself in Blessed Peter, the Prince or head of the Apostles, whose successor is the Roman Pontiff; and since, before all others, she is held to defend the truth of the faith, if any questions should arise concerning the faith, they should be defined by her judgment."
§ 4. Finally, the Council of Florence defined: "The Roman Pontiff stands as the true Vicar of Christ, the head of the whole Church and the father and teacher of all Christians; to him has been given, in Blessed Peter, by Our Lord Jesus Christ, the full power of shepherding, ruling and governing the universal Church."
§ 5. To satisfy this pastoral office, our predecessors always expended untiring effort to see that the saving doctrine of Christ be propagated among all the peoples of the earth, and, with equal care, they watched that it might be preserved pure and sincere where it had been received. Therefore, the bishops of the whole world, sometimes individually, sometimes gathered in synods, following the long-established custom of the Churches and the manner of the ancient rule [of faith] reported back to this Apostolic See those special dangers which arose in matters of faith, so that harm to the faith might be especially repaired in that place where the faith can suffer no defect.
§ 6. Moreover, the Roman Pontiffs, according to the dictates of time and circumstances, sometimes by calling ecumenical councils or asking the opinion of the Church dispersed throughout the world, sometimes through particular synods, sometimes by using other means which divine providence supplied, defined those things which must be held and which they knew, by the help of God, to be consonant with the Sacred Scriptures and apostolic traditions.
§ 7. For the Holy Spirit promised to the successors of Peter, not that they would unfold new doctrine which he revealed to them, but that, with his assistance, they would piously guard and faithfully expound the revelation or deposit of faith handed on through the Apostles.
§ 8. All the venerable Fathers and holy orthodox doctors [=theologians] venerated and followed their [i.e., the successors’ of Peter] apostolic doctrine; they knew full well that this See of St. Peter always remained unstained by all error, according to the divine promise which Our Savior made to the chief of his disciples when he said, 'I have prayed for you, that your faith may not fail, and you, having turned back, strengthen your brothers.'
§ 9. Therefore this charism of truth and unfailing faith was divinely given to Peter and his successors in this chair so that they might fulfill their high office for the salvation of all, so that the whole flock of Christ might, through them, be turned away from the poisonous food of error and be fed on the food of heavenly doctrine, and so that, the occasion of schism being removed, the whole Church might be preserved as one and, firmly grounded on its foundation, might stand against the gates of hell.
§ 10. Since in our times, which especially require the salvific efficacy of the apostolic office, there are found a few who obstruct its authority, we think it is completely necessary to assert solemnly the prerogative which the only-begotten Son of God deigned to unite with the supreme pastoral office.
§ 11. Therefore, faithfully adhering to the tradition received from the beginning of the Christian religion, for the glory of God our Savior, for the exaltation of the Catholic faith and the salvation of the Christian people, with the approval of the sacred Council, we teach and define that it is a divinely revealed dogma that the Roman Pontiff, when he speaks ex cathedra, i.e., when exercising his office as pastor and teacher of all Christians he defines, by his supreme apostolic authority, a doctrine of faith or morals which must be held by the universal Church, enjoys, through the divine assistance, that infallibility promised to him in blessed Peter and with which the divine Redeemer wanted his Church to be endowed in defining doctrine of faith and morals; and therefore that the definitions of the same Roman Pontiff are irreformable of themselves and not from the consent of the Church.
§ 12. Canon. If anyone should presume to contradict this definition of ours - may God prevent this happening -, let him be
anathema.