The Union of Brest at 425

The UNION of Brest (1595–1596) aimed to heal the lack of canonical unity between the Churches. In the spirit of the 1439 Florentine Union, the Orthodox Church of Kievan Metropolia (today's Ukraine and Belarus) sought to rekindle ecclesial union with the Roman Apostolic See. Prominent Roman theologians and curialists made theological, canonical, disciplinary, and liturgical arguments why they should be forced to conform to the prevailing Roman Rite. Instead, Clement VIII achieved an authentic, enduring unity by confirming their ancient customs and particularities. 

Even after the Union, the bishops-delegates were interrogated by curial cardinals as to why they were not wearing the 'proper' vestments. Unity was achieved in diversity, although not all accepted union and "Uniates" were often treated a second-class Catholics.

When Eastern Catholic migrants came to the Americas and western Europe, similar arguments were made, that multiple Rites an Disciplines within the same territory would harm the unity of the Church. Local Roman bishops cited the newcomers' aversion to the majority Rite as proof of the inauthenticity of their Catholicism. They were accused of disobedience, divisiveness, and having schismatic proclivities. One curial cardinal even cited the Fourth Lateran Council.

On closer examination, those fears were more to do with controversies within the local Churches (such as conflicts with Protestants) than going to the peripheries and casting their nets into the deep waters.

Pope Leo XIII (in the 1890s) and Pope Pius XII (after the Second World War) intervened for the marginalised, when the local Churches were too beholden to their own interests to foster unity in diversity. Thus, their names are written in golden letters in the history of the Eastern Catholic Churches.

After 130 years, the Congregation for the Eastern Churches issued a document admitting that earlier curial policies had not properly provided for the early émigré minorities. Significantly, it also admitted that, as a result of those mistakes, 100,000 faithful abandoned the Catholic Communion.

The means used to achieve unity at Brest were far from perfect. Nevertheless, despite every hindrance from tyrants, churchmen, fastidious theologians, and positivist canonists alike, today the Ukrainian Greek-Catholic Church is a Church in its own right (ecclesia sui iuris), with an international hierarchy and more than 6 million faithful on 5 continents. 

Ut unum sint!