First Vatican Council
FIRST VATICAN COUNCIL (1869-1870)
Session 1: Opening of the Council
Session 2: Profession of Faith
Session 3: Dogmatic Constitution on the Catholic Faith
Chapter 1 On God the creator of all things
Chapter 2 On revelation
Chapter 3 On faith
Chapter 4. On faith and reason
1. On God the creator of all things
2. On revelation
3. On faith
4. On faith and reason
Session 4 : 18 July 1870First Dogmatic Constitution on the Church of Christ
Chapter 1. On the institution of the apostolic primacy in blessed Peter
Chapter 2. On the permanence of the primacy of blessed Peter in the Roman pontiffs
Chapter 3. On the power and character of the primacy of the Roman Pontiff
Chapter 4. On the infallible teaching authority of the Roman Pontiff
The definition of Papal Infallibility
This council was summoned by Pope Pius IX by the bull Aeterni Patris of 29 June 1868. The first session was held in St. Peter's basilica on 8 December 1869 in the presence and under the presidency of the Pope.
The purpose of the council was, besides the condemnation of contemporary errors, to define the Catholic doctrine concerning the Church of Christ. In fact, in the three following sessions, there was discussion and approval of only two constitutions: Dogmatic Constitution On The Catholic Faith and First Dogmatic Constitution on the Church of Christ, the latter dealing with the primacy and infallibility of the bishop of Rome. The discussion and approval of the latter constitution gave rise, particularly in Germany, to bitter and most serious controversies which led to the withdrawal from the Church of those known as "Old Catholics".
The outbreak of the Franco-Prussian war led to the interruption of the council. It was in fact never resumed, nor was it ever officially closed. As in other councils at which the Pope was present and presided, the decrees were in the form of bulls, at the end of which was the clear declaration: "with the approval of the sacred council". Very large numbers attended this council, including, for the first time, bishops from outside Europe and its neighboring lands. Bishops from the eastern Orthodox Churches were also invited, but did not come.
The decrees of the council were published in various simultaneous editions. Later they were included in volume 7 of Collectio Lacensis (1892) and in volumes 49-53 of Mansi's collection (1923-1927). The collection which we use is that entitled Acta et decreta sacrosancti oecumenici concilii Vaticani in quatuor prionbus sessionibus, Rome 1872. Comparison with other editions reveals no discrepancies, indeed absolute agreement.
Session 1 : 8 December 1869
Decree of opening of the council
Pius, bishop, servant of the servants of God, with the approval of the sacred council, for an everlasting record. Most reverend fathers, is it your pleasure that, to the praise and glory of the Holy and undivided Trinity, Father, Son and Holy Spirit, for the increase and exaltation of the Catholic faith and religion, for the uprooting of current errors, for the reformation of the clergy and the Christian people, and for the common peace and concord of all, the holy ecumenical Vatican council should be opened, and be declared to have been opened?
[They replied: Yes]
Pius, bishop, servant of the servants of God, with the approval of the sacred council, for an everlasting record. Most reverend fathers, is it your pleasure that the next session of the holy ecumenical Vatican council should be held on the feast of the Epiphany of the Lord, that is 6 January 1870?
[They replied: Yes]
Session 2 : 6 January 1870
Profession of faith
1. I, Pius, bishop of the Catholic Church, with firm faith believe and profess each and every article contained in the profession of faith which the Holy Roman Church uses, namely: I believe in one God the Father almighty, maker of heaven and earth, of all things seen and unseen. And in one Lord Jesus Christ the only-begotten Son of God. Born of the Father before all ages. God from God, light from light, true God from true God. Begotten not made, of one substance with the Father: through whom all things were made. Who for us humans and for our salvation came down from heaven. He was incarnate by the Holy Spirit of the Virgin Mary: and became man. He was crucified also for us, he suffered under Pontius Pilate and was buried. The third day he rose again according to the Scriptures. He ascended into heaven and sits at the right hand of the Father. He shall come again with glory to judge the living and the dead, and of his kingdom there shall be no end. And in the Holy Spirit, the lord and the giver of life, who proceeds from the Father and the Son. Who together with the Father and the Son is adored and glorified: who spoke through the prophets. And one Holy, Catholic and Apostolic Church. I confess one baptism for the remission of Sins. And I look for the resurrection of the dead. And the life of the world to come Amen.
2. Apostolic and ecclesiastical traditions and all other observances and constitutions of that same Church I most firmly accept and embrace.
3. Likewise I accept Sacred Scripture according to that sense which Holy mother Church held and holds, since it is her right to judge of the true sense and interpretation of the Holy Scriptures; nor will I ever receive and interpret them except according to the unanimous consent of the fathers.
4. I profess also that there are seven sacraments of the new law, truly and properly so called, instituted by our lord Jesus Christ and necessary for salvation, though each person need not receive them all. They are:
1. baptism, 2. confirmation, 3. the Eucharist, 4. penance, 5. last anointing, 6. order and 7. matrimony; and they confer grace. Of these baptism, confirmation and order may not be repeated without sacrilege.
5. I likewise receive and accept the rites of the Catholic Church which have been received and approved in the solemn administration of all the aforesaid sacraments.
6. I embrace and accept the whole and every part of what was defined and declared by the holy Council of Trent concerning original sin and justification. Likewise
7. I profess that in the mass there is offered to God a true, proper and propitiatory sacrifice for the living and the dead; and that in the most Holy sacrament of the Eucharist there is truly, really and substantially the body and blood, together with the soul and divinity, of our lord Jesus Christ; and that there takes place the conversion of the whole substance of the bread into his body, and of the whole substance of the wine into his blood, and this conversion the Catholic Church calls transubstantiation.
8. I confess that under either species alone the whole and complete Christ and the true sacrament are received.
9. I firmly hold that purgatory exists, and that the souls detained there are helped by the suffrages of the faithful. Likewise, that the saints reigning with Christ are to be honored and prayed to, and that they offer prayers to God on our behalf, and that their relics should be venerated.
10. I resolutely assert that images of
1. Christ and
2. the ever Virgin Mother of God, and likewise those of
3. the other saints, are to be kept and retained, and that due honor and reverence is to be shown them.
11. I affirm that the power of indulgences was left by Christ in the Church, and that their use is eminently beneficial to the Christian people.
12. I acknowledge the Holy, Catholic, Apostolic and Roman Church, the mother and mistress of all the Churches .
13. Likewise all other things which have been transmitted, defined and declared by the sacred canons and the ecumenical councils, especially the sacred Trent, I accept unhesitatingly and profess; in the same way whatever is to the contrary, and whatever heresies have been condemned, rejected and anathematized by the Church, I too condemn, reject and anathematize.
This true Catholic faith, outside of which none can be saved, which I now freely profess and truly hold, is what I shall steadfastly maintain and confess, by the help of God, in all its completeness and purity until my dying breath, and I shall do my best to ensure  that all others do the same. This is what I, the same Pius, promise, vow and swear. So help me God and these holy gospels of God.
Session 3 : 24 April 1870
Dogmatic constitution on the Catholic faith
Pius, bishop, servant of the servants of God, with the approval of the Sacred Council, for an everlasting record.
1. The Son of God, redeemer of the human race, our lord Jesus Christ, promised, when about to return to his heavenly Father, that he would be with this Church militant upon earth all days even to the end of the world . Hence never at any time has he ceased to stand by his beloved bride, assisting her when she teaches, blessing her in her labors and bringing her help when she is in danger.
2. Now this redemptive providence appears very clearly in unnumbered benefits, but most especially is it manifested in the advantages which have been secured for the Christian world by ecumenical councils, among which the Council of Trent requires special mention, celebrated though it was in evil days.
3. Thence came 1. a closer definition and more fruitful exposition of the holy dogmas of religion and 2. the condemnation and repression of errors; thence too, 3. the restoration and vigorous strengthening of ecclesiastical discipline, 4. the advancement of the clergy in zeal for learning and piety, 5. the founding of colleges for the training of the young for the service of religion; and finally 6. the renewal of the moral life of the Christian people by a more accurate instruction of the faithful, and a more frequent reception of the sacraments. What is more, thence also came 7. a closer union of the members with the visible head, and an increased vigor in the whole mystical body of Christ. Thence came 8. the multiplication of religious orders and other organizations of Christian piety; thence too 9. that determined and constant ardor for the spreading of Christ's kingdom abroad in the world, even at the cost of shedding one's blood.
4. While we recall with grateful hearts, as is only fitting, these and other outstanding gains, which the divine mercy has bestowed on the Church especially by means of the last ecumenical synod, we cannot subdue the bitter grief that we feel at most serious evils, which have largely arisen either because the authority of the sacred synod was held in contempt by all too many, or because its wise decrees were neglected.
5. Everybody knows that those heresies, condemned by the fathers of Trent, which rejected the divine magisterium of the Church and allowed religious questions to be a matter for the judgment of each individual, have gradually collapsed into a multiplicity of sects, either at variance or in agreement with one another; and by this means a good many people have had all faith in Christ destroyed.
6. Indeed even the Holy Bible itself, which they at one time claimed to be the sole source and judge of the Christian faith, is no longer held to be divine, but they begin to assimilate it to the inventions of myth.
7. Thereupon there came into being and spread far and wide throughout the world that doctrine of rationalism or naturalism,utterly opposed to the Christian religion, since this is of supernatural origin,which spares no effort to bring it about that Christ, who alone is our lord and savior, is shut out from the minds of people and the moral life of nations. Thus they would establish what they call the rule of simple reason or nature. The abandonment and rejection of the Christian religion, and the denial of God and his Christ, has plunged the minds of many into the abyss of pantheism, materialism and atheism, and the consequence is that they strive to destroy rational nature itself, to deny any criterion of what is right and just, and to overthrow the very foundations of human society.
8. With this impiety spreading in every direction, it has come about, alas, that many even among the children of the Catholic Church have strayed from the path of genuine piety, and as the truth was gradually diluted in them, their Catholic sensibility was weakened. Led away by diverse and strange teachings  and confusing nature and grace, human knowledge and divine faith, they are found to distort the genuine sense of the dogmas which Holy mother Church holds and teaches, and to endanger the integrity and genuineness of the faith.
9. At the sight of all this, how can the inmost being of the Church not suffer anguish? For just as God wills all people to be saved and come to the knowledge of the truth , just as Christ came to save what was lost  and to gather into one the children of God who were scattered abroad , so the Church, appointed by God to be mother and mistress of nations, recognizes her obligations to all and is always ready and anxious to raise the fallen, to steady those who stumble, to embrace those who return, and to strengthen the good and urge them on to what is better. Thus she can never cease from witnessing to the truth of God which heals all [8 ] and from declaring it, for she knows
that these words were directed to her: My spirit which is upon you, and my words which I have put in your mouth, shall not depart out of your mouth from this time forth and for evermore.
10. And so we, following in the footsteps of our predecessors, in accordance with our supreme apostolic office, have never left off teaching and defending Catholic truth and condemning erroneous doctrines. But now it is our purpose to profess and declare from this chair of Peter before all eyes the saving teaching of Christ, and, by the power given us by God, to reject and condemn the contrary errors. This we shall do with the bishops of the whole world as our co-assessors and fellow-judges, gathered here as they are in the Holy Spirit by our authority in this ecumenical council, and relying on the word of God in Scripture and tradition as we have received it, religiously preserved and authentically expounded by the Catholic Church.
On God the creator of all things
1. The Holy, Catholic, Apostolic and Roman Church believes and acknowledges that there is one true and living God, creator and lord of heaven and earth, almighty, eternal, immeasurable, incomprehensible, infinite in will, understanding and every perfection.
2. Since he is one, singular, completely simple and unchangeable spiritual substance, he must be declared to be in reality and in essence, distinct from the world, supremely happy in himself and from himself, and inexpressibly loftier than anything besides himself which either exists or can be imagined.
3. This one true God, by his goodness and almighty power, not with the intention of increasing his happiness, nor indeed of obtaining happiness, but in order to manifest his perfection by the good things which he bestows on what he creates, by an absolutely free plan, together from the beginning of time brought into being from nothing the twofold created order, that is the spiritual and the bodily, the angelic and the earthly, and thereafter the human which is, in a way, common to both since it is composed of spirit and body .
4. Everything that God has brought into being he protects and governs by his providence, which reaches from one end of the earth to the other and orders all things well . All things are open and laid bare to his eyes , even those which will be brought about by the free activity of creatures.
1. The same Holy mother Church holds and teaches that God, the source and end of all things, can be known with certainty from the consideration of created things, by the natural power of human reason : ever since the creation of the world, his invisible nature has been clearly perceived in the things that have been made.  2. It was, however, pleasing to his wisdom and goodness to reveal himself and the eternal laws of his will to the human race by another, and that a supernatural, way. This is how the Apostle puts it : In many and various ways God spoke of old to our fathers by the prophets; but in these last days he has spoken to us by a Son .
3. It is indeed thanks to this divine revelation, that those matters concerning God which are not of themselves beyond the scope of human reason, can, even in the present state of the human race, be known by everyone without difficulty, with firm certitude and with no intermingling of error.
4. It is not because of this that one must hold revelation to be absolutely necessary; the reason is that God directed human beings to a supernatural end, that is a sharing in the good things of God that utterly surpasses the understanding of the human mind; indeed eye has not seen, neither has ear heard, nor has it come into our hearts to conceive what things God has prepared for those who love him .
5. Now this supernatural revelation, according to the belief of the universal Church, as declared by the sacred Council of Trent, is contained in written books and unwritten traditions, which were received by the apostles from the lips of Christ himself, or came to the apostles by the dictation of the Holy Spirit, and were passed on as it were from hand to hand until they reached us .
6. The complete books of the old and the new Testament with all their parts, as they are listed in the decree of the said Council and as they are found in the old Latin Vulgate edition, are to be received as sacred and canonical.
7. These books the Church holds to be sacred and canonical not because she subsequently approved them by her authority after they had been composed by unaided human skill, nor simply because they contain revelation without error, but because, being written under the inspiration of the Holy Spirit, they have God as their author, and were as such committed to the Church.
8. Now since the decree on the interpretation of Holy Scripture, profitably made by the Council of Trent, with the intention of constraining rash speculation, has been wrongly interpreted by some, we renew that decree and declare its meaning to be as follows: that in matters of faith and morals, belonging as they do to the establishing of Christian doctrine, that meaning of Holy Scripture must be held to be the true one, which Holy mother Church held and holds, since it is her right to judge of the true meaning and interpretation of Holy Scripture.
9. In consequence, it is not permissible for anyone to interpret Holy Scripture in a sense contrary to this, or indeed against the unanimous consent of the fathers.
1. Since human beings are totally dependent on God as their creator and lord, and created reason is completely subject to uncreated truth, we are obliged to yield to God the revealer full submission of intellect and will by faith.
2. This faith, which is the beginning of human salvation, the Catholic Church professes to be a supernatural virtue, by means of which, with the grace of God inspiring and assisting us, we believe to be true what He has revealed, not because we perceive its intrinsic truth by the natural light of reason, but because of the authority of God himself, who makes the revelation and can neither deceive nor be deceived.
3. Faith, declares the Apostle, is the assurance of things hoped for, the conviction of things not seen .
4. Nevertheless, in order that the submission of our faith should be in accordance with reason, it was God's will that there should be linked to the internal assistance of the Holy Spirit external indications of his revelation, that is to say divine acts, and first and foremost miracles and prophecies, which clearly demonstrating as they do the omnipotence and infinite knowledge of God, are the most certain signs of revelation and are suited to the understanding of all.
5. Hence Moses and the prophets, and especially Christ our lord himself, worked many absolutely clear miracles and delivered prophecies; while of the apostles we read: And they went forth and preached every, while the Lord worked with them and confirmed the message by the signs that attended it . Again it is written: We have the prophetic word made more sure; you will do well to pay attention to this as to a lamp shining in a dark place .
6. Now, although the assent of faith is by no means a blind movement of the mind, yet no one can accept the gospel preaching in the way that is necessary for achieving salvation without the inspiration and illumination of the Holy Spirit, who gives to all facility in accepting and believing the truth .
7. And so faith in itself, even though it may not work through charity, is a gift of God, and its operation is a work belonging to the order of salvation, in that a person yields true obedience to God himself when he accepts and collaborates with his grace which he could have rejected.
8. Wherefore, by divine and Catholic faith all those things are to be believed which are contained in the word of God as found in Scripture and tradition, and which are proposed by the Church as matters to be believed as divinely revealed, whether by her solemn judgment or in her ordinary and universal magisterium.
9. Since, then, without faith it is impossible to please God  and reach the fellowship of his sons and daughters, it follows that no one can ever achieve justification without it, neither can anyone attain eternal life unless he or she perseveres in it to the end.
10. So that we could fulfill our duty of embracing the true faith and of persevering unwaveringly in it, God, through his only begotten Son, founded the Church, and he endowed his institution with clear notes to the end that she might be recognized by all as the guardian and teacher of the revealed word.
11. To the Catholic Church alone belong all those things, so many and so marvelous, which have been divinely ordained to make for the manifest credibility of the Christian faith.
12. What is more, the Church herself by reason of her astonishing propagation, her outstanding holiness and her inexhaustible fertility in every kind of goodness, by her Catholic unity and her unconquerable stability, is a kind of great and perpetual motive of credibility and an incontrovertible evidence of her own divine mission.
13. So it comes about that, like a standard lifted up for the nations , she both invites to herself those who have not yet believed, and likewise assures her sons and daughters that the faith they profess rests on the firmest of foundations.
14. To this witness is added the effective help of power from on high. For, the kind Lord stirs up those who go astray and helps them by his grace so that they may come to the knowledge of the truth  ; and also confirms by his grace those whom he has translated into his admirable light , so that they may persevere in this light, not abandoning them unless he is first abandoned.
15. Consequently, the situation of those, who by the heavenly gift of faith have embraced the Catholic truth, is by no means the same as that of those who, led by human opinions, follow a false religion; for those who have accepted the faith under the guidance of the Church can never have any just cause for changing this faith or for calling it into question.
This being so, giving thanks to God the Father who has made us worthy to share with the saints in light  let us not neglect so great a salvation , but looking unto Jesus the author and finisher of our faith , let us hold the unshakable confession of our hope .
On faith and reason
1. The perpetual agreement of the Catholic Church has maintained and maintains this too: that there is a twofold order of knowledge, distinct not only as regards its source, but also as regards its object.
2. With regard to the source, we know at the one level by natural reason, at the other level by divine faith.
3. With regard to the object, besides those things to which natural reason can attain, there are proposed for our belief mysteries hidden in God which, unless they are divinely revealed, are incapable of being known.
Wherefore, when the Apostle, who witnesses that God was known to the gentiles from created things , comes to treat of the grace and truth which came by Jesus Christ , he declares: We impart a secret and hidden wisdom of God, which God decreed before the ages for our glorification. None of the rulers of this age understood this. God has revealed it to us through the Spirit. For the Spirit searches everything, even the depths of God . And the Only-begotten himself, in his confession to the Father, acknowledges that the Father has hidden these things from the wise and prudent and revealed them to the little ones .
4. Now reason, does indeed when it seeks persistently, piously and soberly, achieve by God's gift some understanding, and that most profitable, of the mysteries, whether by analogy from what it knows naturally, or from the connection of these mysteries with one another and with the final end of humanity; but reason is never rendered capable of penetrating these mysteries in the way in which it penetrates those truths which form its proper object.
For the divine mysteries, by their very nature, so far surpass the created understanding that, even when a revelation has been given and accepted by faith, they remain covered by the veil of that same faith and wrapped, as it were, in a certain obscurity, as long as in this mortal life we are away from the Lord, for we walk by faith, and not by sight .
5. Even though faith is above reason, there can never be any real disagreement between faith and reason, since it is the same God who reveals the mysteries and infuses faith, and who has endowed the human mind with the light of reason.
6. God cannot deny himself, nor can truth ever be in opposition to truth. The appearance of this kind of specious contradiction is chiefly due to the fact that either the dogmas of faith are not understood and explained in accordance with the mind of the Church, or unsound views are mistaken for the conclusions of reason.
7. Therefore we define that every assertion contrary to the truth of enlightened faith is totally false .
8. Furthermore the Church which, together with its apostolic office of teaching, has received the charge of preserving the deposit of faith, has by divine appointment the right and duty of condemning what wrongly passes for knowledge, lest anyone be led astray by philosophy and empty deceit .
9. Hence all faithful Christians are forbidden to defend as the legitimate conclusions of science those opinions which are known to be contrary to the doctrine of faith, particularly if they have been condemned by the Church; and furthermore they are absolutely bound to hold them to be errors which wear the deceptive appearance of truth.
10. Not only can faith and reason never be at odds with one another but they mutually support each other, for on the one hand right reason established the foundations of the faith and, illuminated by its light, develops the science of divine things; on the other hand, faith delivers reason from errors and protects it and furnishes it with knowledge of many kinds.
11. Hence, so far is the Church from hindering the development of human arts and studies, that in fact she assists and promotes them in many ways. For she is neither ignorant nor contemptuous of the advantages which derive from this source for human life, rather she acknowledges that those things flow from God, the lord of sciences, and, if they are properly used, lead to God by the help of his grace.
12. Nor does the Church forbid these studies to employ, each within its own area, its own proper principles and method: but while she admits this just freedom, she takes particular care that they do not become infected with errors by conflicting with divine teaching, or, by going beyond their proper limits, intrude upon what belongs to faith and engender confusion.
13. For the doctrine of the faith which God has revealed is put forward not as some philosophical discovery capable of being perfected by human intelligence, but as a divine deposit committed to the spouse of Christ to be faithfully protected and infallibly promulgated.
14. Hence, too, that meaning of the sacred dogmas is ever to be maintained which has once been declared by Holy mother Church, and there must never be any abandonment of this sense under the pretext or in the name of a more profound understanding.
May understanding, knowledge and wisdom increase as ages and centuries roll along, and greatly and vigorously flourish, in each and all, in the individual and the whole Church: but this only in its own proper kind, that is to say, in the same doctrine, the same sense, and the same understanding .
1. On God the creator of all things
1. If anyone denies the one true God, creator and lord of things visible and invisible: let him be anathema.
2. If anyone is so bold as to assert that there exists nothing besides matter: let him be anathema.
3. If anyone says that the substance or essence of God and that of all things are one and the same: let him be anathema.
4. If anyone says that finite things, both corporal and spiritual, or at any rate, spiritual, emanated from the divine substance; or that the divine essence, by the manifestation and evolution of itself becomes all things or, finally, that God is a universal or indefinite being which by self determination establishes the totality of things distinct in genera, species and individuals: let him be anathema.
5. If anyone does not confess that the world and all things which are contained in it, both spiritual and material, were produced, according to their whole substance, out of nothing by God; or holds that God did not create by his will free from all necessity, but as necessarily as he necessarily loves himself; or denies that the world was created for the glory of God: let him be anathema.
2. On revelation
1. If anyone says that the one, true God, our creator and lord, cannot be known with certainty from the things that have been made, by the natural light of human reason: let him be anathema.
2. If anyone says that it is impossible, or not expedient, that human beings should be taught by means of divine revelation about God and the worship that should be shown him : let him be anathema.
3. If anyone says that a human being cannot be divinely elevated to a knowledge and perfection which exceeds the natural, but of himself can and must reach finally the possession of all truth and goodness by continual development: let him be anathema.
4. If anyone does not receive as sacred and canonical the complete books of Sacred Scripture with all their parts, as the holy Council of Trent listed them, or denies that they were divinely inspired : let him be anathema.
3. On faith
1. If anyone says that human reason is so independent that faith cannot be commanded by God: let him be anathema.
2. If anyone says that divine faith is not to be distinguished from natural knowledge about God and moral matters, and consequently that for divine faith it is not required that revealed truth should be believed because of the authority of God who reveals it: let him be anathema.
3. If anyone says that divine revelation cannot be made credible by external signs, and that therefore men and women ought to be moved to faith only by each one's internal experience or private inspiration: let him be anathema.
4. If anyone says that all miracles are impossible, and that therefore all reports of them, even those contained in Sacred Scripture, are to be set aside as fables or myths; or that miracles can never be known with certainty, nor can the divine origin of the Christian religion be proved from them: let him be anathema.
5. If anyone says that the assent to Christian faith is not free, but is necessarily produced by arguments of human reason; or that the grace of God is necessary only for living faith which works by charity: let him be anathema.
6. If anyone says that the condition of the faithful and those who have not yet attained to the only true faith is alike, so that Catholics may have a just cause for calling in doubt, by suspending their assent, the faith which they have already received from the teaching of the Church, until they have completed a scientific demonstration of the credibility and truth of their faith: let him be anathema.
4. On faith and reason
1. If anyone says that in divine revelation there are contained no true mysteries properly so-called, but that all the dogmas of the faith can be understood and demonstrated by properly trained reason from natural principles: let him be anathema.
2. If anyone says that human studies are to be treated with such a degree of liberty that their assertions may be maintained as true even when they are opposed to divine revelation, and that they may not be forbidden by the Church: let him be anathema.
3. If anyone says that it is possible that at some time, given the advancement of knowledge, a sense may be assigned to the dogmas propounded by the Church which is different from that which the Church has understood and understands: let him be anathema.
And so in the performance of our supreme pastoral office, we beseech for the love of Jesus Christ and we command, by the authority of him who is also our God and savior, all faithful Christians, especially those in authority or who have the duty of teaching, that they contribute their zeal and labor to the warding off and elimination of these errors from the Church and to the spreading of the light of the pure faith.
But since it is not enough to avoid the contamination of heresy unless those errors are carefully shunned which approach it in greater or less degree, we warn all of their duty to observe the constitutions and decrees in which such wrong opinions, though not expressly mentioned in this document, have been banned and forbidden by this Holy See.
Session 4 : 18 July 1870
First dogmatic constitution on the Church of Christ
Pius, bishop, servant of the servants of God, with the approval of the Sacred Council, for an everlasting record.
1. The eternal shepherd and guardian of our souls , in order to render permanent the saving work of redemption, determined to build a Church in which, as in the house of the living God, all the faithful should be linked by the bond of one faith and charity.
2. Therefore, before he was glorified, he besought his Father, not for the apostles only, but also for those who were to believe in him through their word, that they all might be one as the Son himself and the Father are one .
3. So then, just as he sent apostles, whom he chose out of the world , even as he had been sent by the Father , in like manner it was his will that in his Church there should be shepherds and teachers until the end of time.
4. In order, then, that the episcopal office should be one and undivided and that, by the union of the clergy, the whole multitude of believers should be held together in the unity of faith and communion, he set blessed Peter over the rest of the apostles and instituted in him the permanent principle of both unities and their visible foundation.
5. Upon the strength of this foundation was to be built the eternal temple, and the Church whose topmost part reaches heaven was to rise upon the firmness of this foundation .
6. And since the gates of hell trying, if they can, to overthrow the Church, make their assault with a hatred that increases day by day against its divinely laid foundation, we judge it necessary, with the approbation of the Sacred Council, and for the protection, defense and growth of the Catholic flock, to propound the doctrine concerning the 1. institution, 2. permanence and 3. nature of the sacred and apostolic primacy, upon which the strength and coherence of the whole Church depends.
7. This doctrine is to be believed and held by all the faithful in accordance with the ancient and unchanging faith of the whole Church.
8. Furthermore, we shall proscribe and condemn the contrary errors which are so harmful to the Lord's flock.
On the institution of the apostolic primacy in blessed Peter
1. We teach and declare that, according to the gospel evidence, a primacy of jurisdiction over the whole Church of God was immediately and directly promised to the blessed apostle Peter and conferred on him by Christ the lord.
2. It was to Simon alone, to whom he had already said You shall be called Cephas , that the Lord, after his confession, You are the Christ, the son of the living God, spoke these words:
Blessed are you, Simon Bar-Jona. For flesh and blood has not revealed this to you, but my Father who is in heaven. And I tell you, you are Peter, and on this rock I will build my Church, and the gates of the underworld shall not prevail against it. I will give you the keys of the kingdom of heaven, and whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven  .
3. And it was to Peter alone that Jesus, after his resurrection, confided the jurisdiction of Supreme Pastor and ruler of his whole fold, saying:
Feed my lambs, feed my sheep .
4. To this absolutely manifest teaching of the Sacred Scriptures, as it has always been understood by the Catholic Church, are clearly opposed the distorted opinions of those who misrepresent the form of government which Christ the lord established in his Church and deny that Peter, in preference to the rest of the apostles, taken singly or collectively, was endowed by Christ with a true and proper primacy of jurisdiction.
5. The same may be said of those who assert that this primacy was not conferred immediately and directly on blessed Peter himself, but rather on the Church, and that it was through the Church that it was transmitted to him in his capacity as her minister.
6. Therefore, if anyone says that blessed Peter the apostle was not appointed by Christ the lord as prince of all the apostles and visible head of the whole Church militant; or that it was a primacy of honor only and not one of true and proper jurisdiction that he directly and immediately received from our lord Jesus Christ himself: let him be anathema.
On the permanence of the primacy of blessed Peter in the Roman pontiffs
1. That which our lord Jesus Christ, the prince of shepherds and great shepherd of the sheep, established in the blessed apostle Peter, for the continual salvation and permanent benefit of the Church, must of necessity remain for ever, by Christ's authority, in the Church which, founded as it is upon a rock, will stand firm until the end of time .
2. For no one can be in doubt, indeed it was known in every age that the holy and most blessed Peter, prince and head of the apostles, the pillar of faith and the foundation of the Catholic Church, received the keys of the kingdom from our lord Jesus Christ, the savior and redeemer of the human race, and that to this day and for ever he lives and presides and exercises judgment in his successors the bishops of the Holy Roman See, which he founded and consecrated with his blood .
3. Therefore whoever succeeds to the chair of Peter obtains by the institution of Christ himself, the primacy of Peter over the whole Church. So what the truth has ordained stands firm, and blessed Peter perseveres in the rock-like strength he was granted, and does not abandon that guidance of the Church which he once received .
4. For this reason it has always been necessary for every Church--that is to say the faithful throughout the world--to be in agreement with the Roman Church because of its more effective leadership. In consequence of being joined, as members to head, with that see, from which the rights of sacred communion flow to all, they will grow together into the structure of a single body .
5. Therefore, if anyone says that it is not by the institution of Christ the lord himself (that is to say, by divine law) that blessed Peter should have perpetual successors in the primacy over the whole Church; or that the Roman Pontiff is not the successor of blessed Peter in this primacy: let him be anathema.
On the power and character of the primacy of the Roman Pontiff
1. And so, supported by the clear witness of Holy Scripture, and adhering to the manifest and explicit decrees both of our predecessors the Roman Pontiffs and of general councils, we promulgate anew the definition of the ecumenical Council of Florence , which must be believed by all faithful Christians, namely that the Apostolic See and the Roman Pontiff hold a world-wide primacy, and that the Roman Pontiff is the successor of blessed Peter, the prince of the apostles, true vicar of Christ, head of the whole Church and father and teacher of all Christian people.
To him, in blessed Peter, full power has been given by our lord Jesus Christ to tend, rule and govern the universal Church.
All this is to be found in the acts of the ecumenical councils and the sacred canons.
2. Wherefore we teach and declare that, by divine ordinance, the Roman Church possesses a pre-eminence of ordinary power over every other Church, and that this jurisdictional power of the Roman Pontiff is both episcopal and immediate. Both clergy and faithful, of whatever rite and dignity, both singly and collectively, are bound to submit to this power by the duty of hierarchical subordination and true obedience, and this not only in matters concerning faith and morals, but also in those which regard the discipline and government of the Church throughout the world.
3. In this way, by unity with the Roman Pontiff in communion and in profession of the same faith , the Church of Christ becomes one flock under one Supreme Shepherd .
4. This is the teaching of the Catholic truth, and no one can depart from it without endangering his faith and salvation.
5. This power of the Supreme Pontiff by no means detracts from that ordinary and immediate power of episcopal jurisdiction, by which bishops, who have succeeded to the place of the apostles by appointment of the Holy Spirit, tend and govern individually the particular flocks which have been assigned to them. On the contrary, this power of theirs is asserted, supported and defended by the Supreme and Universal Pastor; for St. Gregory the Great says: "My honor is the honor of the whole Church. My honor is the steadfast strength of my brethren. Then do I receive true honor, when it is denied to none of those to whom honor is due." 
6. Furthermore, it follows from that supreme power which the Roman Pontiff has in governing the whole Church, that he has the right, in the performance of this office of his, to communicate freely with the pastors and flocks of the entire Church, so that they may be taught and guided by him in the way of salvation.
7. And therefore we condemn and reject the opinions of those who hold that this communication of the Supreme Head with pastors and flocks may be lawfully obstructed; or that it should be dependent on the civil power, which leads them to maintain that what is determined by the Apostolic See or by its authority concerning the government of the Church, has no force or effect unless it is confirmed by the agreement of the civil authority.
8. Since the Roman Pontiff, by the divine right of the apostolic primacy, governs the whole Church, we likewise teach and declare that he is the supreme judge of the faithful , and that in all cases which fall under ecclesiastical jurisdiction recourse may be had to his judgment . The sentence of the Apostolic See (than which there is no higher authority) is not subject to revision by anyone, nor may anyone lawfully pass judgment thereupon . And so they stray from the genuine path of truth who maintain that it is lawful to appeal from the judgments of the Roman pontiffs to an ecumenical council as if this were an authority superior to the Roman Pontiff.
9. So, then, if anyone says that the Roman Pontiff has merely an office of supervision and guidance, and not the full and supreme power of jurisdiction over the whole Church, and this not only in matters of faith and morals, but also in those which concern the discipline and government of the Church dispersed throughout the whole world; or that he has only the principal part, but not the absolute fullness, of this supreme power; or that this power of his is not ordinary and immediate both over all and each of the Churches and over all and each of the pastors and faithful: let him be anathema.
On the infallible teaching authority of the Roman Pontiff
1. That apostolic primacy which the Roman Pontiff possesses as successor of Peter, the prince of the apostles, includes also the supreme power of teaching. This Holy See has always maintained this, the constant custom of the Church demonstrates it, and the ecumenical councils, particularly those in which East and West met in the union of faith and charity, have declared it.
2. So the fathers of the fourth Council of Constantinople, following the footsteps of their predecessors, published this solemn profession of faith: The first condition of salvation is to maintain the rule of the true faith. And since that saying of our lord Jesus Christ, You are Peter, and upon this rock I will build my Church , cannot fail of its effect, the words spoken are confirmed by their consequences. For in the Apostolic See the Catholic religion has always been preserved unblemished, and sacred doctrine been held in honor. Since it is our earnest desire to be in no way separated from this faith and doctrine, we hope that we may deserve to remain in that one communion which the Apostolic See preaches, for in it is the whole and true strength of the Christian religion .
What is more, with the approval of the second Council of Lyons, the Greeks made the following profession:
"The Holy Roman Church possesses the supreme and full primacy and principality over the whole Catholic Church. She truly and humbly acknowledges that she received this from the Lord himself in blessed Peter, the prince and chief of the apostles, whose successor the Roman Pontiff is, together with the fullness of power. And since before all others she has the duty of defending the truth of the faith, so if any questions arise concerning the faith, it is by her judgment that they must be settled." 
Then there is the definition of the Council of Florence:
"The Roman Pontiff is the true vicar of Christ, the head of the whole Church and the father and teacher of all Christians; and to him was committed in blessed Peter, by our lord Jesus Christ, the full power of tending, ruling and governing the whole Church." 
3. To satisfy this pastoral office, our predecessors strove unwearyingly that the saving teaching of Christ should be spread among all the peoples of the world; and with equal care they made sure that it should be kept pure and uncontaminated wherever it was received.
4. It was for this reason that the bishops of the whole world, sometimes individually, sometimes gathered in synods, according to the long established custom of the Churches and the pattern of ancient usage referred to this Apostolic See those dangers especially which arose in matters concerning the faith. This was to ensure that any damage suffered by the faith should be repaired in that place above all where the faith can know no failing .
5. The Roman pontiffs, too, as the circumstances of the time or the state of affairs suggested, sometimes by summoning ecumenical councils or consulting the opinion of the Churches scattered throughout the world, sometimes by special synods, sometimes by taking advantage of other useful means afforded by divine providence, defined as doctrines to be held those things which, by God's help, they knew to be in keeping with Sacred Scripture and the apostolic traditions.
6. For the Holy Spirit was promised to the successors of Peter not so that they might, by his revelation, make known some new doctrine, but that, by his assistance, they might religiously guard and faithfully expound the revelation or deposit of faith transmitted by the apostles.
Indeed, their apostolic teaching was embraced by all the venerable fathers and reverenced and followed by all the holy orthodox doctors, for they knew very well that this See of St. Peter always remains unblemished by any error, in accordance with the divine promise of our Lord and Savior to the prince of his disciples: I have prayed for you that your faith may not fail; and when you have turned again, strengthen your brethren .
7. This gift of truth and never-failing faith was therefore divinely conferred on Peter and his successors in this See so that they might discharge their exalted office for the salvation of all, and so that the whole flock of Christ might be kept away by them from the poisonous food of error and be nourished with the sustenance of heavenly doctrine. Thus the tendency to schism is removed and the whole Church is preserved in unity, and, resting on its foundation, can stand firm against the gates of hell.
8. But since in this very age when the salutary effectiveness of the apostolic office is most especially needed, not a few are to be found who disparage its authority, we judge it absolutely necessary to affirm solemnly the prerogative which the only-begotten Son of God was pleased to attach to the supreme pastoral office.
9. Therefore, faithfully adhering to the tradition received from the beginning of the Christian faith, to the glory of God our savior, for the exaltation of the Catholic religion and for the salvation of the Christian people, with the approval of the Sacred Council, 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.
So then, should anyone, which God forbid, have the temerity to reject this definition of ours: let him be anathema.
Given at Rome in public session, solemnly held in the Vatican Basilica in the year of our Lord one thousand eight hundred and seventy, on the eighteenth day of July, in the twenty-fifth year of Our Pontificate.
In conformity with the original.
Joseph, Bishop of St. Polten Secretary to the Vatican Council
1 The Profession of faith of the other fathers added: and I pledge and swear true obedience to the Roman Pontiff, successor of blessed Peter the Prince of the Apostles, and Vicar of Jesus Christ
2 The profession of faith of the other fathers continues: my subjects, or those for whom I have responsibility in virtue of my office, hold, teach and preach the same
3 See Mt 28, 20.
4 See Heb 13, 9.
5 1 Tm 2, 4.
6 Lk 19, 10.
7 Jn 11, 52.
8 See Wis 16, 12.
9 Is 59, 21.
10 See Lateran Council IV, const. 1 (see above, p. 230).
11 Wis 8, 1.
12 Heb 4, 13.
13 Rm 1, 20.
14 Heb 1, 1-2.
15 1 Cor 2, 9.
16 Council of Trent, session 4, first decree (see above p. 663).
17 Heb 11, 1.
18 Mk 16, 20.
19 2 Pt 1, 19.
20 Council of Orange II (529), canon 7 (Bruns 2, 178; Msi 8, 713).
21 Heb 11, 6.
22 Is 11, 12.
23 1 Tm 2, 4.
24 1 Pt 2, 9; Col 1, 13.
25 Col 1, 12.
26 Heb 2, 3.
27 Heb 12, 2.
28 Heb 10, 12.
29 Rm 1, 20.
30 Jn 1, 17.
31 i Cor 2, 7-8, 10.
32 Mt 11, 25.
33 2 Cor 5, 6-7.
34 See Lateran Council V, session 8 (see above p. 605).
35 See Col 2, 8.
36 Vincent of Lerins, Commonitorium (Notebook), 28 (PL 50, 668).
37 1 Pt 2,25.
38 Jn 17, 20-21.
39 Jn 15, 19.
40 Jn 20, 21.
41 Leo 1, Serm. (Sermons), 4 (elsewhere 3), ch. 2 for the day of his birth (PL 54, 150).
42 Jn 1, 42.
43 Mt 16, 16 19.
44 Jn 21, 15-17.
45 See Mt 7, 25; Lk 6, 48.
46 From the speech of Philip, the Roman legate, at the 3rd session of the Council of Ephesus (D no. 112).
47 Leo I, Serm. (Sermons), 3 (elsewhere 2), ch. 3 (PL 54, 146).
48 Irenaeus, Adv. haeres. (Against Heresies) 1113 (PG 7, 849), Council of Aquilea (381), to be found among: Ambrose, Epistolae (Letters), 11 (PL 16, 946).
49 Council of Florence, session 6 (see above p. 528).
50 See Jn 10, 16.
51 Ep. ad Eulog. Alexandrin. (Letter to Eulogius of Alexandria), VIII 29 (30) (MGH, Ep. 2, 31 28-30, PL 77, 933).
52 Pius VI, Letter Super soliditate dated 28 Nov. 1786.
53 From Michael Palaeologus's profession of faith which was read out at the second Council of Lyons (D no. 466).
54 Nicholas I, Ep. ad Michaelem imp. (Letter to the emperor Michael) (PL 119, 954).
55 Mt 16, 18.
56 From Pope Hormisdas's formula of the year 517 (D no. 171), see above p. 157 n. 1.
57 From Michael Palaeologus's profession of faith which was read out at the second Council of Lyons (D no. 466).
58 Council of Florence, session 6 (see above p. 528). S Bernard, Ep. (Letters) 190 (PL 182, 1053).
59 Bernard, Ep. (Letters) 190 (PL 182, 1053).
60 Lk 22, 32.
The translation found here is that which appears in Decrees of the Ecumenical Councils ed. Norman Tanner. S.J. The numbering of the canons is however found in Tanner's text.