Eastern Christianity took a firm root in Ukraine in 989 when Vladimir, Prince of Kiev, embraced the Christian Faith and was baptized. Soon afterwards many missionaries from the Byzantine Empire arrived, having been sent by the Patriarch of Constantinople to preach the Gospel.
When the Church of Rome and the Church of Constantinople severed ties with one another in the 11th century, the Church in Ukraine gradually followed suit and finally gave up the bonds of unity with Rome. When Ukrainian Orthodox bishops met at a council in Brest-Litovsk in 1595, seven bishops decided to re-establish communion with Rome. Guaranteed that their Byzantine tradition and Liturgy would be respected and recognized by Rome, they and many priests and lay faithful were re-united with the See of Rome, while others continued to remain Orthodox.
In the 19th century many Ukrainian Catholics began to emigrate to North America, bringing their pastors, traditions and liturgy to Canada and the United States. Under Communist rule, Catholics in Ukraine were persecuted, with many being imprisoned and murdered; in 1945 all the Ukrainian Catholic bishops were arrested or killed.
Today the Ukrainian Catholic Church is the largest Eastern Catholic Church, with about 5 million faithful. It is led by His Beatitude Sviatoslav Shevchuk , Major Archbishop of Kyiv-Galicia. His election was confirmed by Pope Benedict XVI on March 25, 2011.
In the United States the Ukrainian Catholic Archeparchy of Philadelphia is headed by Metropolitan-Archbishop Borys Gudziak , newly appointed by Pope Francis on February 18, 2019. The Archeparchy is composed of the Eparchies of Stamford, Chicago, and Parma.
The Eparchy of St. Nicholas in Chicago, Illinois, is headed by Bishop Benedict Aleksiychuk who was enthroned as Bishop on June 29, 2017. He is responsible for all Ukrainian Catholics in the United States west of Ohio, Kentucky, Tennessee, and Mississippi. There are currently around 70 priests and deacons working in the eparchy in 46 parishes and mission stations, including the parish of the Nativity of the Mother of God Ukrainian Catholic Church.
In addition the Ruthenian Catholic Archeparchy of Pittsburgh is composed of the Ruthenian eparchies of Parma, Passaic and Phoenix. These are also under the authority of the Pope.