From Apostolic Letter on the Fourth Centenary of the Union of Brest from John Paul II:http://www.byzcath.org/index.php/resources-mainmenu-63/document-library-mainmenu-124/32-documents-from-rome/302-apostolic-letter-for-the-fourth-centenary-of-the-union-of-brest
In search of unity
2. The celebrations commemorating the Union of Brest must be seen in the context of the Millennium of the Baptism of the Rus'. Seven years ago, in 1988, that event was celebrated with great solemnity. For the occasion I published two documents: the Apostolic Letter Euntes in mundum of 25 January 1988,5 for the whole Church, and the Message Magnum Baptismi donum, of 14 February of the same year,6 addressed to Ukrainian Catholics. It was an occasion for celebrating a moment of fundamental importance for the Christian and cultural identity of those peoples, a moment of unique significance, since at that time the Churches of the Byzantine tradition and the Church of Rome were still living in full communion.
After the division which damaged the unity between the West and the Byzantine East, frequent and intense efforts were made to restore full communion. I wish to mention two particularly significant events: the Second Council of Lyons in 1274, and above all the Council of Florence in 1439, when protocols of union with the Eastern Churches were signed. Unfortunately, various causes prevented the promise and potential of those agreements from being realized.
The Bishops of the Metropolia of Kiev, in restoring communion with Rome, made explicit reference to the decisions of the Council of Florence, a Council which had numbered among its participants representatives from the Patriarchate of Constantinople.
In this context, the figure of Metropolitan Isidore of Kiev stands out. As a faithful interpreter and defender of the decisions of that Council, he had to endure exile for his convictions.
The Bishops who promoted the union and the members of their Church retained a lively awareness of their original close ties to their Orthodox brethren, together with a full consciousness of the Oriental identity of their Metropolia, an identity which was also to be upheld after the union. In the history of the Catholic Church, it is a highly significant fact that this just desire was respected and that the act of union did not involve passing over to the Latin tradition, as some thought would happen. Their Church saw an acknowledgment of its right to be governed by its own hierarchy with a specific discipline and to maintain its Eastern liturgical and spiritual heritage.
Between persecutionand growth
3. After the union, the Ukrainian Greek Catholic Church enjoyed a period in which its ecclesiastical structures flourished, with resulting benefits for religious life, the education of the clergy and the spiritual commitment of the faithful. With remarkable farsightedness, great importance was attached to education. Thanks to the valuable contribution of the Basilian Order and other Religious Congregations, there was a great growth in the study of the sacred sciences and the nation's culture. In the present century, a figure of extraordinary prestige, in this regard as well as in his witness of suffering borne for Christ, was Metropolitan Andrii Sheptyckyi, whose education and fine spiritual qualities were combined with outstanding organizational gifts. He founded schools and academies, supported theological studies and the human sciences, the press and sacred art, and sought to preserve historical memories.
And yet, all this ecclesial vitality was continually marked by the tragedy of misunderstanding and opposition. An illustrious victim in this regard was the Archbishop of Polock and Vitebsk, Josaphat Kuntsevych, whose martyrdom merited the unfading crown of eternal glory. His body now lies in the Vatican Basilica, where it is continuously venerated with devotion and gratitude by Catholics from throughout the world.
The difficulties and trials continued unabated. Pope Pius XII recalled them in the Encyclical Letter Orientales omnes. After describing the earlier persecutions, he predicted the tragic persecution which would take place under the atheistic regime.7
Outstanding among the heroic witnesses to the rights not only of the faith but also of human conscience in those difficult years is the figure of Metropolitan Josyf Slipyj: his courage in enduring exile and prison for 18 years and his indomitable confidence in the resurrection of his Church make him one of the most powerful figures among the confessors of the faith in our time. Nor should his many companions in punishment be forgotten, particularly Bishops Hryhory Khomyshyn and Josaphat Kocylowskyj.
These tempestuous events shook the Church in the homeland to its roots. But Divine Providence had already begun to make it possible for many of its members to find a way of escape for themselves and their people. From the beginning of the 19th century onwards, great waves of emigrants began to cross the ocean, settling above all in Canada, the United States of America, Brazil, Argentina and Australia. The Holy See took care to be close to them, by providing assistance and establishing pastoral structures for them in their new homes, including the establishment of their own Eparchies. At the time of trial, during the atheistic persecution in their native land, the voice of these believers could thus be raised, in full freedom, with strength and courage. In the international forum they defended the right of their persecuted brethren to religious freedom, and thus strengthened the Second Vatican Council's appeal for religious freedom,8 and the efforts made in this regard by the Holy See.
4. The whole Catholic Community recalls with deep emotion the victims of such great suffering: the martyrs and confessors of the faith of the Church in Ukraine offer us a magnificent lesson in fidelity even at the price of life itself. And we, the favoured witnesses of their sacrifice, are aware that they helped to maintain the dignity of a world which seemed overwhelmed by atrocities. They knew the truth, and the truth set them free. Christians in Europe and throughout the world, pausing in prayer before the concentration camps and prisons, should be grateful for the light which they gave: it was the light of Christ, which they caused to shine in the darkness. For long years the darkness seemed in the eyes of the world to prevail, but it was not able to extinguish that light, which was the light of God and the light of man, wounded but not laid low.
This inheritance of suffering and glory today stands at a historic crossroads: now that the chains of imprisonment have been broken, the Greek Catholic Church in Ukraine has begun again to breathe in freedom and to regain fully its own active role in the Church and in history. This task, difficult yet providential, today calls for particular reflection, that it may be carried out with wisdom and farsightedness.