I wanted to show you a picture from my book about various national dances in the Soviet Union. This one represents Belarus:
In the book there is the following statement:
Балет "Князь Озеро", музыка В. Золотарева - полесская легенда о борбе народа с польско-литовскими феодалами - удостоен в 1950 году Сталинской премии.
The ballet "Prince Lake", musics by V. Zolotarev - a legend about the fight of the (Belarussian) nation with the Polish-Lithuanian feudals - was given a Stalin premium in 1950.
Well, this is unfortunately true. They (the Ruthenians) were conquered by Lithuania, about 80% of the people spoke Ruthenian there (in Lithuania). But the situation was not so bad, at least concerning the religion. The Orthodox religion was tolerated until under Sigismund the IIIrd influenced by the Jesuits the infamous Union of Brest was declared in the 1596. Then the trouble began. This Union was in fact delegalizing the Orthodox hierarchy.