Few subjects aroused the attention of the Council Fathers at Vatican II more than the effort to restore unity among Christians, a task known by the term “ecumenism.”

The Council’s concern for this topic was present throughout its work, especially in its reflection on the Church, and would be the specific theme of the Decree Unitatis Redintegratio. The Council approved this text on Nov. 21, 1964, on the same solemn occasion as the promulgation of the dogmatic constitution on the Church, Lumen Gentium, as well as the decree on the Catholic Churches of the Eastern Rite, Orientalium Ecclesiarum.  

The concern for unity among Christians, present from the very origins of the Church, took on particular force in the early 20th century in what has come to be known as the Ecumenical Movement.  

From the initial announcement of the Second Vatican Council in January 1959, Pope St. John XXIII had wanted the assembly to be a renewed invitation to unity for the faithful of separated Christian communities. This sentiment would resonate deeply among the Council Fathers, as well as more broadly in the Church and the world as a whole.  

By the start of the Council, in October of 1962, the preparatory commissions had produced no less than three separate documents on the topic of Christian unity. At the end of the Council’s first period, the Council Fathers overwhelmingly voted to fuse these three documents into one, entrusting the task to the Secretariat for Christian Unity.  

With this decision, the Council made a resolute choice to follow an authentic ecumenical sensibility, represented by the secretariat and its president, the German Jesuit and Scripture scholar Cardinal Augustin Bea. Nonetheless, the Council debates would also make some significant adjustments to the draft produced by the Secretariat and sent to the Council Fathers in Spring 1963.  

On Nov. 18, 1963, the Council began discussing the draft on ecumenism and would continue to do so over the course of more than 10 general meetings. Many Council Fathers agreed that the text marked a new beginning in the relations between the Catholic Church and other Christian communities.  

The Melkite Greek Catholic Patriarch Maximos IV Sayegh, an outspoken voice for unity during the Council, called the draft a sign that Catholics had left behind a period of “sterile polemic,” with regard to the Eastern Orthodox, and instead had embraced an attitude of sincere faith and charity. Speaking in French rather than the prescribed Latin, the Patriarch stated that the proposed text furthermore marked the beginning of a “true theology of Church,” rooted in the perspective of the Church as a communion of the Father and the Son in the Holy Spirit. Such a vision, as he noted, was vital to the Eastern tradition. 

Such an ecumenical mindset on the part of the Church, as the draft indicated, was not simply a question of rhetorical tactics, but needed to come from a profound interior renewal. The text composed by the Secretariat affirmed a principle that would find its way into the definitive version of the Decree: 

“There can be no ecumenism worthy of the name without a change of heart.” 

The Council Fathers would specifically vote to put more emphasis on the need for conversion with the Church, and the final text of the decree describes Christ’s call to a “continual reformation” in the Church, “in so far as she is an institution of men here on earth.”  

These assertions were part of an authentically ecumenical attitude, which the Tanzanian Cardinal Laurean Rugambwa described as being marked by “humility, an open mind, true charity, flowing from the heart of Christ himself.” 

The French Bishop Léon Arthur Elchinger, shortly afterward, proclaimed that the time had come for the Church to recognize and confess the historical truth, however bitter it might be. With such a statement he did not claim, as he said, to negate the truth that the Church is one, holy, catholic, and apostolic, but only that “God placed his gifts in earthen vessels (2 Corinthians 4:7), that is in sinful men.” Bishop Elchinger argued that Christians and their pastors, while possessing the truth, had mistreated separated Christians who had perceived certain other truths of Revelation. At other times, as he also remarked, in moments of polemic, Catholics had rejected certain teachings as false which were not completely false.  

Other Council Fathers sought to emphasize that such an attitude of humility and charity did not mean negating the Catholic Church’s unique identity, or “the very fullness of grace and truth entrusted to the Church,” as the decree would maintain. The Polish Bishop Jan Mazur, speaking in the name of all the bishops of his country, called on the Council to be more explicit and clear about the premises of ecumenism. The Auxiliary Bishop of Lublin stated that ecumenism does not mean obscuring the revealed truth, nor any kind of indifference on the part of Catholics, but rather is the fruit of ardent and profound faith and an exercise in true charity.  

The final text of Unitatis Redintegratio would respond to such desires for clarity, as voiced by Mazur and many others, and includes several new passages that elucidate the particular identity of the Catholic Church with respect to other Churches and Christian communities. With such affirmations, Unitatis Redintegratio manifests that authentic ecumenism does not imply any kind of weakening of conviction on the part of Catholics. As the French Bishop Gabriel-Marie Garrone had commented during the Council debate, ecumenism is founded in a faith that is “firm and inflexible,” and in “fearless hope,” connected to God’s own will for unity and to that charity infused into the hearts of Christians by the Holy Spirit (Romans 5:5).  

This supernatural attitude led the Council to profess that, beyond the divisions, a real communion — though “imperfect” — exists between the Catholic Church and all who believe and are baptized. The decree makes a groundbreaking recognition of “significant elements and endowments” — such as the written Word of God, the life of grace, as well as visible elements — present among separated Christian communities. The document also takes care to note that such elements “belong by right to the one Church of Christ.”  

The Council was by no means blind to the serious difficulties and obstacles in the way of Christian Unity. Speaking from the experience of the Church in England and Wales, Bishop George Patrick Dwyer of Leeds warned against the idea that charitable words and cordial relations would be enough to restore Christian unity. Nonetheless, while describing the serious differences in belief, he acknowledged that the Catholic Church is called to maintain an attitude of hope and follow the path of dialogue.  

Such is the mindset present in Unitatis Redintegratio, in which the Council admits the “many obstacles, sometimes serious ones, to full ecclesiastical communion.” While frankly admitting such challenges and the reality of human limitation, with this historic decree the Council firmly directed the Church along the path of ecumenism, resting all of its hope — as the document states in concluding — “on the prayer of Christ for the Church, on our Father’s love for us, and on the power of the Holy Spirit.”

Sixty years later, while giving thanks for the many steps forward, yet aware of the long distance yet to travel to reach full visible unity, the Church is called to keep alive this same fervent trust.