The Ukrainian Greek Catholic Church (UGCC) is a major archiepiscopal sui iuris ("autonomous") Eastern Catholic church that is based in Ukraine. As a particular church of the Catholic Church, it is in full communion with the Holy See. The major archbishop presides over the entire Church but is not distinguished with the patriarchal title. The incumbent Major Archbishop is Sviatoslav Shevchuk.
The church regards itself as a successor to the metropolis that was established in 988 following the Christianization of Kievan Rus' by Grand Prince Vladimir the Great. Following the establishment of the metropolis of Kiev, Galicia and all Rus', by the terms of the Union of Brest, the Ruthenian church was transferred from the ecclesiastical jurisdiction of the Ecumenical Patriarchate of Constantinople to the jurisdiction of the Holy See in 1596, thereby forming the Ruthenian Uniate Church. The Union of Brest was a treaty between the Ruthenian Orthodox Church in the Polish–Lithuanian Commonwealth, under the leadership of the metropolitan of Kiev, Galicia and all Rus'—Michael III—on one part, and the Latin Church under the leadership of Pope Clement VIII on the other part.
