Better known as the “April 15, 2012 Doctrinal Declaration” for its eventual signature date, this was the secret “doctrinal preamble” which the major superiors of the SSPX (sans Bishop Williamson) met to discuss in Albano, Italy in October, 2011.
Despite widespread dissatisfaction with the terms of this “preamble,” Bishop Fellay would announce a few months later, in Winona, MN, that he was ready to accept a merely practical accord with modernist Rome. Shortly thereafter, the Letter of the Three Bishops surfaced, imploring Bishop Fellay not to accept the deal. Bishop Fellay’s incredible response to the bishops will be contained in Appendix V, below.
The day after that response, Bishop Fellay signed this modernist doctrinal declaration, and submitted it to Benedict XVI. But seeing the tumult which was made within the Society, and desirous of the formal reorientation of the SSPX he hoped to obtain through Bishop Fellay at the upcoming General Chapter meeting just a few months later, Benedict rejected Bishop Fellay’s declaration, and instead made an even more outrageous counteroffer (requiring complete submission to Vatican II and the post-conciliar reforms), which he knew Bishop Fellay must reject. This maneuver would create the impression of Bishop Fellay rejecting the modernist formulation and holding the line, thereby working to restabilize his authority within the Society, until the Chapter meeting. It was by this means that Benedict helped Bishop Fellay survive the 2012 General Chapter, and officially revise its position vis-à-vis Rome.
Interestingly, Bishop Fellay seems not to have understood the purpose of Benedict’s rejection, at least initially, as a letter soon aired in which he inquired of the pope to see what had happened to their understanding, explaining that he had withstood significant opposition within the Society in order to push it through. It was apparently lost on him that Benedict was interested in capturing the entire Society (and allied religious groups), not just one bishop, leaving the other three free to carry on with Tradition. A few months later, the Pope would get his wish: His man (Fellay) survived, and the ralliement became official policy in the General Chapter Declaration.
I
We promise to be always faithful to the Catholic Church and to the Roman Pontiff, the Supreme Pastor, Vicar of Christ, Successor of Peter, and head of the body of bishops.
II
We declare that we accept the teachings of the Magisterium of the Church in the substance of Faith and Morals, adhering to each doctrinal affirmation in the required degree, according to the doctrine contained in No.25 of the dogmatic constitution Lumen Gentium of the Second Vatican Council.(1)
III
1. We declare that we accept the doctrine regarding the Roman Pontiff and regarding the college of bishops, with the Pope as its head, which is taught by the dogmatic constitution Pastor Aeternus of Vatican I and by the Dogmatic Constitution Lumen Gentium of Vatican II, chapter 3 (de constitutione hierarchica Ecclesiae et in specie de episcopatu), explained and interpreted by the nota explicativa praevia in this same chapter.
2. We recognise the authority of the Magisterium to which alone is given the task of authentically interpreting the word of God, in written form or handed down (2) in fidelity to Tradition, recalling that “the Holy Ghost was not promised to the successors of Peter in order for them to make known, through revelation, a new doctrine, but so that with His assistance they may keep in a holy and expressly faithful manner the revelation transmitted by the Apostles, that is to say, the Faith.”(3)
3. Tradition is the living transmission of revelation “usque as nos“(4) and the Church in its doctrine, in its life and in its liturgy perpetuates and transmits to all generations what this is and what She believes. Tradition progresses in the Church with the assistance of the Holy Ghost(5), not as a contrary novelty(6), but through a better understanding of the Deposit of the Faith(7).
4. The entire tradition of Catholic Faith must be the criterion and guide in understanding the teaching of the Second Vatican Council, which, in turn, enlightens - in other words deepens and subsequently makes explicit - certain aspects of the life and doctrine of the Church implicitly present within itself or not yet conceptually formulated(8).
5. The affirmations of the Second Vatican Council and of the later Pontifical Magisterium relating to the relationship between the Church and the non-Catholic Christian confessions, as well as the social duty of religion and the right to religious liberty, whose formulation is with difficulty reconcilable with prior doctrinal affirmations from the Magisterium, must be understood in the light of the whole, uninterrupted Tradition, in a manner coherent with the truths previously taught by the Magisterium of the Church, without accepting any interpretation of these affirmations whatsoever that would expose Catholic doctrine to opposition or rupture with Tradition and with this Magisterium.
6. That is why it is legitimate to promote through legitimate discussion the study and theological explanations of the expressions and formulations of Vatican II and of the Magisterium which followed it, in the case where they don’t appear reconcilable with the previous Magisterium of the Church(9).
7. We declare that we recognize the validity of the sacrifice of the Mass and the Sacraments celebrated with the intention to do what the Church does according to the rites indicated in the typical editions of the Roman Missal and the Sacramentary Rituals legitimately promulgated by Popes Paul VI and John-Paul II.
8. In following the guidelines laid out above (III,5), as well as Canon 21 of the Code of Canon Law, we promise to respect the common discipline of the Church and the ecclesiastical laws, especially those which are contained in the Code of Canon Law promulgated by John-Paul II (1983) and in the Code of Canon Law of the Oriental Churches promulgated by the same pontiff (1990), without prejudice to the discipline of the Society of Saint Pius X, by a special law.
Notes--
(1) Cf. the new formula for the Profession of Faith and the Oath of Fidelity for assuming a charge exercised in the name of the Church, 1989; cf. Code of Canon Law, canon 749,750, §2; 752; CCEO canon 597; 598, 1 & 2; 599.
(2) Cf. Pius XII, Humani Generis encyclical.
(3) Vatican I, Dogmatic Constitution, Pastor Aeternus, Dz. 3070.
(4) Council of Trent, Dz. 1501: “All saving truth and rules of conduct (Matt. 16:15) are contained in the written books and in the unwritten traditions, which, received by the Apostles from the mouth of Christ Himself, or from the Apostles themselves,[3] the Holy Ghost dictating, have come down to us, transmitted as it were from hand to hand.”
(5) Cf. Second Vatican Council, Dogmatic Constitution Dei Verbum, 8 & 9, Denz. 4209-4210.
(6) Vatican I, Dogmatic Constitution Dei Filius, Dz. 3020: “Hence, also, that understanding of its sacred dogmas must be perpetually retained, which Holy Mother Church has once declared; and there must never be recession from that meaning under the specious name of a deeper understanding “Therefore […] let the understanding, the knowledge, and wisdom of individuals as of all, of one man as of the whole Church, grow and progress strongly with the passage of the ages and the centuries; but let it be solely in its own genus, namely in the same dogma, with the same sense and the same understanding.’‘ [Vincent of Lerins, Commonitorium, 23, 3].”
(7) Vatican I, Dogmatic Constitution Dei Filius, Dz. 3011; Anti-modernist Oath, no. 4; Pius XII, Encyclical Letter Humani Generis, Dz 3886; Vatican Council II, Dogmatic Constitution Dei Verbum, 10, Dz. 4213.
(8) For example, like the teaching on the sacraments and the episcopacy in Lumen Gentium, no. 21.
(9) There is a parallel in history in the Decree for the Armenians of the Council of Florence, where the porrection of the instruments was indicated as the matter of the sacrament of Order. Nevertheless theologians legitimately discussed, even after this decree, the accuracy of such an assertion. Pope Pius XII finally resolved the issue in another way.
www.therecusant.com/doctrinalpreamble-15apr2012



To paraphrase Cardinals Ottaviani and Bacci: "This agreement represents, both as a whole and in its details, a striking departure from the Catholic faith and a surrender to the Conciliar religion".
How could Msgr. Fellay ever put his signature to this?