History
By the end of 12th century Europe was generally divided into two large areas: western area with dominance of Roman Catholicism and eastern with Orthodox and Byzantine influences. Border between them was roughly along the Bug River. This placed area, currently known as Belarus, into a unique position where these two influences mixed and interfered.
Before the 14th century Russian Orthodox church was dominant in Belarus. Union of Krewo in 1385 broke this monopoly and made Catholicism the religion of the ruling class. Jogaila, then ruler of Lithuania, part of which was Belarus, ordered to convert all population of Lithuania into Catholicism. 1.5 years after Union of Krewo Wilno episcopate was created which received a lot of land from the Lithuanian dukes. By the middle of 16th century Catholicism became strong in Lithuania and bordering with it north-west parts of Belarus. But Orthodox church was still dominant in Belarus.
In 16th century crisis began in Christianity: Protestant Reformation began in Catholicism and heresy period began in an Orthodox area. From the 50th years of 16th century Protestantism ideas began spreading in Lithuanian state, part of which was Belarus. The first Protestant Church in Belarus was created in Brest by Mikołaj "the Black" Radziwiłł.
Read more about this topic: Religion In Belarus