The Ukrainian Greek Catholic Church traditionally constituted the second largest group of believers after the Christian Orthodox churches. The Union of Brest formed the Church in 1596 to unify Orthodox and Catholic believers. Outlawed by the Soviet Union in 1946 and legalized in 1987, the church was for forty-three years the single largest banned religious community in the world. Major Archbishop Sviatoslav Shevchuk is the present head of the Ukrainian Greek Catholic Church. The church uses Ukrainian as its liturgical language.